San Pedro Atocpan
San Pedro Atocpan is one of the communities that make up the borough of Milpa Alta in the Federal District of Mexico, better known as Mexico City. This location is known for the preparation of mole sauce, which employs over 90% of the community and provides all of the sauce, eaten in Mexico City. Despite being in the Federal District and the second largest district in size, Milpa Alta is distinctly rural. Only 116,000 of Mexico City's 8 million inhabitants live in the entire borough, as of 2005, only 8,997 lived in San Pedro Atocpan; the name "Atocpan" is from Nahuatl and means "on fertile soil" The community is located in the northwest of the borough, on the highway between Mexico City and Oaxtepec, Morelos. It has a territory of 87.65 hectares, is about 2,500 meters above sea level. The land here is rugged as it is wedged between the Cuauhtzin Teutli Mountain; this community was designated as a "Barrio Mágico" by the city in 2011. The community is best known for the preparation of mole, a traditional sauce that comes in a variety of flavors.
Modern mole is derived from a pre-Hispanic preparation called "chilmulli," which in Nahuatl means "chili pepper sauce" During the colonial period, this sauce was modified by adding ingredients such as nuts, sesame seeds and spices such as cinnamon. While the flavors have multiplied and changed, the consistency of the sauce has remained the same. 92% of the community's population makes a living related to the preparation and sale of the sauce. The moles of San Pedro Atocpan are not made in factories but rather in small family-owned enterprises. Moles of different flavors, smells and textures are made, but the specialty is "mole almendrado", invented here and made with between 26 and 28 ingredients, always with a base of three chili peppers: mulato and ancho; the recipe is well-guarded. Many of these small businesses have networked to find ways to buy the more than twenty ingredients most moles need, such as chili peppers from Zacatecas, eliminating the need for middlemen; each family in the town has its own recipes for the various types of moles.
The family of Guadalupe Rios, for example, adds apple to her moles to avoid digestive problems. Seventy years ago, life in San Pedro Atocpan was similar to just about any other rural community growing corn and beans. At that time only four neighborhoods prepared mole for town festivals: Panchimalco, Ocotitla and Tula, but those who prepared it were prominent women in their communities. In the 1940s, one family had the idea of making the long trek to Mexico City proper to sell some of their mole at the La Merced market, it was successful, but they brought with them only two kilos, since it was made by hand grinding the ingredients. With the paving of the main road and the introduction of electricity in 1947, it became easier to make and transport mole to the city. Since a sauce, traditionally made for family use became a commodity for the town; the town now produces 60% of the mole made in Mexico and 89% of the mole consumed in Mexico City, adding up to between 28,000 and 30,000 tons of mole produced each year.
The community has two main churches: the Parish of San Pedro Apostol and the Church of Señor de la Misericordias. The Parish of San Pedro Apostol is a Franciscan church, dedicated on 28 August 1680 and declared a national monument in 1933, its patron of Saint Peter is celebrated on 29 of June of each year. The other church, Señor de las Misericordias is a modern building, dedicated to an image of Christ, venerated in all of Milpa Alta; this church hosts a festival to this image each May that brings people from other parts of the delegation as well as the neighboring states of Morelos and Mexico State. The National Festival of Mole is hosted at the location each year in October, it began in 1977 with the specific aim of promoting the town's product. The first festival was not held in the San Pedro Atocpan proper, but in the neighborhood of Yenhuitlalpan with only four restaurants participating, it was held not in October but rather in May to coincide with the festival in honor of the Señor de las Misericordias.
However, this caused problems with people who did not like the idea of taking advantage of a religious festival for commercial purposes. So the mole festival was moved to October; the annual festival has crafts, traditional Mexican music, carnival rides and other fair attractions. Today, over 2,600 people participate to bring the event together and prepare about 400,000 plates of different mole dishes such as pork chops and rabbit in adobo and turkey in mole almendrado and mole verde but the favorites are enchiladas made with various traditional moles
Pueblo Culhuacán is an designated neighborhood of the Iztapalapa borough of Mexico City, which used to be a major pre Hispanic city. Ancient Culhuacán was founded around 600 CE and the site has been continuously occupied since; the city was conquered by the Aztecs in the 15th century, but the Aztecs considered the city to have status with early rulers marrying into Culhua nobility to legitimize themselves. After the Spanish conquest of the Aztec Empire, the Franciscans and the Augustinians made Culhuacán a major evangelization center, with the latter building the monastery complex which remains to this day. Today, Culhucan is integrated into Mexico City physically and politically; this area was designated as a "Barrio Mágico" by the city in 2011. Culhuacan is one of the subdivisions of the borough of Iztapalapa, bordering the borough of Coyoacán. Geographically, it is located at the base of the Cerro de la Estrella mountain. Today, the area known as Culhuacan is politically divided into eleven units, called “colonias,” “barrios” or “pueblos” with the historic center designated as Pueblo Culhuacán, due its earlier independent status as an altepetl and as a recognized pueblo by the Spanish colonial government.
The area was separate and rural as late as early 20th century, made up of chinampas separated by a series of canals. The Culhuacan area is now physically and politically integrated into Mexico City, covered in modern cinderblock and cement structures that continue uninterrupted into neighboring areas. Line 12 of the Mexico City Metro passes through the Pueblo with the elevated station Pueblo Culhuacán only a couple of blocks from the central 16th century monastery complex. What is now Avenida Tláhuac was a canal in the colonial period; this canal was a main waterway connecting Mexico City with the agricultural areas of Chalco and Xochimilco with flat bottomed canoes called trajineras carrying produce to the city. In the mid 20th century, this canal was filled in and paved over to create the current road. Line 12 of the Metro here is elevated following this same road. To this day, the residents of this area maintain a kind of rivalry with those from the historic center of Iztapalapa on the other side of the Cerro de la Estrella.
Both host passion plays during Holy Week and each have a small natural cave which contains an image of the buried Christ as a local pilgrimage site. Culhuacan’s cave site is marked by a chapel called the Capilla del Señor del Calvario, it refers to the image was is said to have been found over 200 years ago by quarry workers in this cave. The name comes from Nahuatl and means “place of the culhuas.” The term “culhua” means “ancient or venerable” but it can mean “hunched” which might refer to the Cerro de la Estrella. However, the area was considered by the Mexica to be an ancient religious and mythical place as a connection to the cultural past. Culhuacan was founded in 600 CE and was a center of influence in the lake are of the Valley of Mexico; the Ramírez Codex says that this city was recognized by the Mexica as a contemporary to the mythical Aztlán and of the ancestors of the peoples who were in the Valley of Mexico before the Aztecs. The early Mexica leaders married women from Culhuacan. Culhuacan’s prime was between the fall of Tula and the rise of Tenochtitlan, making it a major power in the Valley of Mexico for three hundred years.
Culhuacán was located on the north coast of the Lake Chalco/Lake Xochimilco, which has since dried up. According to archeological studies, the site appears to have been continuously inhabited since its initial founding; until between 600 and 800 CE, it was an important provincial city under the domination of Teotihuacan. Between 800 and 900 CE, it became governed by a Toltec-Chichimeca dynasty, which dominated much of the south of the Valley of Mexico. Between 900 and 1000 CE, along with Tula and Otumba, formed the nucleus of the Toltec empire; when this fell, Culhuacan became a haven for the last of the Tula ruling class. The city declined but despite this, it remained the most powerful in the valley until the rise of Tenochtitlan in the 15th century; however nothing remains of the pre-Hispanic settlement because it was destroyed, with the exception of the temple at the Cerro de la Estrella, which became the center of the Aztec’s 52-year renewal ceremony. A great deal is known about colonial-era Culhuacan the late sixteenth century.
Cullhuacan was the subject of a Relación Geografica, a project by the Spanish crown to systematically gather data on indigenous communities. Many of these reports to the crown had pictorial maps drawn by indigenous scribes accompanying them. A fragment of the first baptismal register survives; the richest source of Culhuacan’s history is a collection of last wills and testaments and other documents in Nahuatl from the period 1580-1600, now found in the collections of the Universidad Iberoamericana. The analysis of the information in the Nahuatl wills has made possible the writing of a social history of the town at a particular period in its colonial history, an example of the New Philology; the monastery of San Juan Evangelista is one of the few remaining from the 16th century in Mexico City. It is located on Avenida 10 between Avenida Tláhuac. After the Spanish conquest of the Aztec Empire, Culhuacan was selected as an evangelization center first by the Franciscans and by the Augustinians; the Franciscans founded a small mission over the ruins of the Culhuacan main temple.
They were replaced by the Augustinians between 1552 and 1569, who replaced the Franciscan mission with a monastery and church. This monastery was dedicated to th
Colonia Roma called La Roma or Roma, is a district located in the Cuauhtémoc borough of Mexico City just west of the city’s historic center, in fact is no longer a single colonia but now two defined ones, Roma Norte and Roma Sur, divided by Coahuila street. The colonia was planned as an upper-class Porfirian neighborhood in the early twentieth century, it became a middle-class neighborhood in slow decline, with the downswing being worsened by the 1985 Mexico City earthquake. Since the 2000s, the area has seen increased re-gentrification. Roma and neighbouring Condesa are known for being the epicenter of hipster subculture in the city, rivals Polanco as the center of the city's culinary scene. Besides residential buildings, the neighbourhood streets are lined with restaurants, clubs, cultural centers and galleries. Many are housed in former Art Nouveau and Neo-Classical buildings dating from the Porfiriato period at the beginning of the 20th century. Roma was designated as a "Barrio Mágico" by the city in 2011.
The area was a shallow part of Lake Texcoco, dotted with tiny islands and one small island village of Aztacalco during the pre-Hispanic period. During the colonial period, the area dried up and became rural lands first owned by Hernán Cortés and by the Counts of Miraville. In the late 19th and early 20th centuries, this area west of what was Mexico City proper was being turned into “modern” colonias for the wealthy seeking to escape the deterioration of city center; the colonia’s height as an “aristocratic” and “European” enclave was from its founding in the 1900s until about the 1940s. However, wealthy residents began to move to newer neighborhoods as early as the 1940s and problems associated with urbanization began to appear in the 1950s. Older mansions began to give way to modern commercial buildings in the 1960s and 1970s as the deterioration became more serious; the 1985 Mexico City earthquake caused widespread destruction in the colonia to newer and more commercial and apartment buildings causing one major development to disappear.
Since there have been efforts to conserve the area’s architectural heritage and regain some of its former prestige with some success. Roma's borders are: Avenida Chapultepec to the north, across, the Zona Rosa, Colonia Juárez area Avenida de los Insurgentes to the west, across, the Condesa district Eje 4 Sur Benjamin Franklin, Antonio M. Anza and Viaducto Miguel Alemán to the south, across which are Colonia del Valle and Colonia Narvarte Avenidas Cuauhtémoc and Jalapa to the east, across, Colonia Doctores In addition, a section lies west of Insurgentes, whose borders are Chapultepec, Av. Veracruz, Parque España/Avenida Álvaro Obregón Avenida Coahuila divides Roma into the official neighborhoods of Roma Norte and Roma Sur. Roma consists of several sub-areas: Roma Norte II and III, east of Avenida de los Insurgentes and north of Av. Coahuila, bisected by Roma's signature boulevard, Avenida Álvaro Obregón, is where the vast majority of the hippest restaurants, clubs, etc. are found. It is home to about 1,100 mansions and other architecturally and important structures built between 1906 and 1939.
Most of these are no longer cultural centers and other businesses. Examples of these adaptations include the Casa Lamm Cultural Center, the Casa Universitaria del Libro, the main building of the Universidad de Londres and the various art galleries which are found on Colima street. In the northeast corner of this area is the pre-Hispanic village of La Romita. La Romita is a small section of Roma which used to be an independent village and colonia and whose streets are still different from the rest of Roma; the territory of modern Colonia Roma in pre-Hispanic times consisted of the shallow waters of Lake Texcoco and a number of small islands of firm ground, on one of which stood the village of Aztacalco. It was an independent village until the early 20th century, when it was made its own colonia in 1903 with the name of La Romita; when Colonia Roma was created, Romita was incorporated into it, but the local residents fought redevelopment. The area has since developed semi-independently from the rest of Colonia Roma, both in infrastructure and socially.
Today, the area is difficult to access, with narrow streets leading to a small plaza and church called Santa María de la Natividad de Aztacalco. The local residents were of a lower social class than the rest of Roma, with the wealthy residents avoiding it for fear of thieves; the area still has a reputation for crime and is found at the extreme northeast of the colonia near Metro Cuauhtémoc. Roma Norte I, west of Insurgentes, has fewer landmark buildings and is a mix of offices, restaurants and residential; the Palacio de Hierro department store Durango branch occupies a city block here and the landmark Fuente de Cibeles fountain is at the center of a major cluster of restaurants, cafés and clubs. East of Insurgentes and south of Coahuila street, Roma Sur is much more traditional than hip Roma Norte. There are restaurants and shops catering to them; the Mercado Medellín is famous for Latin American goods and food as well. In the far southeast corner of Roma stands the Centro Urbano Benito Juárez, or Multifamiliar Juárez, a large apartment complex in the 1940s and early 1950s.
It was one of several projects of this type by architect Mario Pani, designed to house city government workers and to be semi-autonomous with its own schools, businesses etc. and inco
Condesa or La Condesa is an area in the Cuauhtémoc Borough of Mexico City, south of the Zona Rosa and 4 to 5 km west of the Zócalo, the city's main square. It is west of Colonia Roma, together with which it is designated as a "Barrio Mágico Turístico". Together they are referred to as Condesa–Roma, one of the most architecturally significant and bastion of the creative communities of the city, it consists of three colonias or recognized neighborhoods: Colonia Condesa, Colonia Hipódromo and Colonia Hipódromo Condesa. The area is considered to be fashionable and popular with younger businesspeople and pet lovers, it features a lot of nightclubs. "Condesa" means "countess" and it is named after María Magdalena Dávalos de Bracamontes y Orozco, the Countess of Miravalle, whose lands stretched from what is now Colonia Roma to Tacubaya. The area began as lands belonging to two countesses in the colonial period. By the 19th century and early 20th century, the process of subdividing this land was begun although Colonia Condesa proper would not be established until the early 20th century.
The Condesa as a whole, consisting of the three colonias, is bordered by: Av. Veracruz, Av. Álvaro Obregón and Av. Yucatán on the north/northeast, across, Colonia Roma Norte Avenida de los Insurgentes Sur on the east, across which are Col. Roma Norte and Col. Roma Sur Eje 4 Sur on the south, across, Colonia Escandón in Miguel Hidalgo borough Circuito Interior on the west/northwest, across, Colonia San Miguel ChapultepecThe three colonias are located as follows: Colonia Hipódromo lies to the east of Av. Tamaulipas and Parque España Colonia Condesa lies west of Av. Tamaulipas and north of Av. Michoacán Colonia Hipódromo Condesa lies west of Av. Tamaulipas and south of Av. Michoacán Condesa is considered fashionable among young businesspeople, pet lovers and others. There are some wide avenues and lined with trees, it is filled with restaurants, cafés, boutiques and art galleries. Some of these shops include the Rosario Castellanos bookstore, which includes a cáfe, an auditorium theatre and a children’s room, the Bar Malverde, with its lucha libre theme, the Café La Gloria, around for over a decade.
Most of the bars and cafes are concentrated along Michoacán avenues. While the area has been residential, its “Bohemian” character has only been in existence since late 1980s. While longtime residents complain about noise and other disturbances, the overall reputation of the area continues to grow and attract more restaurants. Most of these residents are young and affluent, with only two of the areas 13 K-8 schools being public. Condesa as well as Roma and Centro Histórico was affected by the 1985 earthquake, this event is part of the history and memory of the inhabitants of the neighborhood. Many buildings survived and are now examples of Art Deco architecture, as well as innovative modern designs, which give it an overall urban touch. Many buildings date back to the 1920s, such is the case of the Condesa DF hotel, housed in a 1928 apartment complex. In addition, a lot of new apartment buildings have been built on the sites of former original demolished houses and other infill sites; the Edificio San Martín, by Ernesto Buenrostro) and the Edificio México are representative examples of Art Deco architecture in Mexico, popular in the 1930s.
By the late 1990s, the San Martín was nearly in ruins, but it was restored between 1998 and 2001 by architect Carlos Duclaud. While Duclaud made some changes to the interior, most of the original plan of the building remains intact. One major change was made. In the 1930s, apartment building windows with the best views were in the bedrooms, rather than in the living room and dining room; this was switched by rearranging interior walls. However, the facades, most of the public areas such as stairwells, were kept true to the original, with the aim of keeping the building's original “identity”; the Basurto Building is an Art Deco building, noted for its use of curved and straight lines in its form. It was built on irregularly shaped land. Others built the structure but he authorized the use of his name; the structure was designed by Serrano on Avenida México with a view of Parque México and the Popocatepetl Plaza. Overlooking this Parque España in Colonia Roma section is a mansion that belonged to Fernando Torreblanca, personal secretary to Álvaro Obregón, Hortensia Elias Calles.
It was designed by engineer Manuel Luis Stampa. The mansión is now the el Fideicomiso Archivos Plutarco Elías Calles y Fernando Torreblanca, which houses many documents related to the country’s history after the Mexican Revolution. Michoacán Market in a 1946 building designed in the Functionalist style of Modernist architecture, with market stalls and prepared food stands; the medians of Avenida Ámsterdam, which runs as an oval around Parque México, as well as the medians of avenidas Campeche, Benjamín Hill and Alfonso Reyes, are lined with trees and plants on either side of pedestrian paths that run down the middle. Parque México was the center of the racetrack that used to occupy Colonia Hipódromo, not only serves as the center of that colonia, it is the defining element of the entire Condesa area; the park is considered to be the “lungs” of this portion of the city. It was designed as the center of the original, larger Condesa neighborhood during one of its planning phases in the 1920s; the rest of the old hacienda had been parceled into resid
Cuajimalpa de Morelos is one of the 16 boroughs of Mexico City. It is located on the west side of the Federal District in the Sierra de las Cruces mountains which separate Mexico City from the State of Mexico; the borough is named after the former rural town of Cuajimalpa, which has since been absorbed by urban sprawl. The borough is home to the Desierto de los Leones National Park, the first declared in Mexico as well as the second largest annual passion play in Mexico City; the proper name of the borough is Cuajimalpa de Morelos. The borough was named after the prominent community and former municipality of San Pedro Cuajimalpa which remains the seat of local government. "Cuajimalpa" is derived from the Nahuatl "Cuauhximalpan". The appendage of “de Morelos” was added in 1970 to honor José María Morelos, a hero of the Mexican War of Independence. In 1342 the Tepanecas established themselves in the area, controlling the forests for about 100 years from their capital in Azcapotzalco; when the Tepanecas were overthrown by the Aztec Triple Alliance in the mid 15th century, many fled to this rugged terrain.
During the Spanish conquest, Hernán Cortés subdued settlements in the area such as Santa Rosa, Santa Lucía, Cuauhximalpan and Acopilco to secure the roads leading to the Toluca Valley. In 1534, Cortés took personal control of lands in the area, calling it San Pedro Cuauhximalpa and established towns such as San Lorenzo Acopilco, San Mateo Tlaltenango and San Pablo Chimalpa. In the 17th century the Carmelites founded a hermitage and monastery called Desierto de los Leones, today a museum and national park. At this time, the indigenous population of the area recovered enough that there were efforts to reclaim lost territory and government. To this end, a type of codex called “techialoayan” was created to document the history of indigenous communities to make legal claims. One of the most important of this is the Techialoyan Codex of Cuajimalpa, it describes a solemn meeting of authorities to confirm the extension and political organization of the area. Written in Nahuatl, it remained a valid legal document until 1865, when Emperor Maximilian I had it translated into Spanish.
Today the original document is part of the Mexican Federal Archives. In 1997, the document was named as part of the “Memory of the World” by UNESCO. From the colonial period into the 19th and early 20th centuries, the most common economic activities in the area were the harvesting of firewood and the making of charcoal, with some raising of crops and livestock for domestic consumption; the area was important as a way station, providing lodging and food to travelers between the Valley of Mexico and the Toluca Valley. In 1884, a rail line was constructed through the same area. In the early 19th century, the first insurgent army under Miguel Hidalgo y Costilla arrived at the area, with Hidalgo himself staying at the Mesón San Luisito; the town of Cuajimalpa was made the seat of a municipality in 1862. During the last decades of the 19th century and into the 20th modern services such as running water, paved roads and electric lighting were introduced. A number of industries related to construction supplies were founded.
During the Mexican Revolution there were clashes in the area between forces loyal to Venustiano Carranza and Emiliano Zapata in El Contadero and San Pedro. One story from the time says that the Zapatistas cut the ears of the inhabitants of the town of Cuajimalpa to distinguish them from those loyal to Carranza. In 1929, the area's status was changed from municipality to borough with the reorganization of the Federal District of Mexico City. Although it remained rural until the 1930s, its main economic activities were in decline with many moving to Mexico City. Prior to the 1950s, urbanization of the area was limited because of its terrain. In the mid 20th century, the industrialization of the Valley of Mexico began to reach the borough of Cuajimalpa; the population of the area increased over 900% from 1950 to 1980, with the highest rate of growth in the 1970s. New residential construction fueled the growth, covering former forest and agricultural areas in areas such as San Lorenzo Acopilco, Las Lajas, La Pila, Las Maromas, Cola de Pato, Cruz Blanca, Chancocoyotl, Tlapeaca and Pito Real.
These include large residential subdivisions such as El Contadero and Lomas de Vista Hermosa, as well as unregulated settlements on the sides of hills and small canyons. The pace of growth remained high in the 1980s, in part due to the 1985 earthquake, which prompted many to move away from the soft soils of the city center into the more solid rock of the west and south of the valley. However, the rapid development began to cause environmental problems, including the building over former pit mines, used as landfills. In the 1990s, efforts were begun to protect natural areas. Much of the territory has been urbanized and contains some of the city's most expensive residential and commercial real estate, with newer developments for upper classes pushing out lower income groups. In the 1990s and 2000s there were changes in the borough's borders due to the settlements of disputes between the Federal District and the State of Mexico; the Cuajimalpa borough is located on the west side of the Federal District of Mexico City.
To the west of it are the municipalities of Ocoyoacac and Huixquilucan de Degollado in the State of Mexico. It borders the boroughs of Miguel Hidalgo, Alvaro Obregon and Magdalena Contreras in the Federal District; the borough covers an area of 8,905 hectares, just over five percent of the total of the Federal District. The borough is situated on the east side of the Sierra de las Cruces, a volc
International Standard Serial Number
An International Standard Serial Number is an eight-digit serial number used to uniquely identify a serial publication, such as a magazine. The ISSN is helpful in distinguishing between serials with the same title. ISSN are used in ordering, interlibrary loans, other practices in connection with serial literature; the ISSN system was first drafted as an International Organization for Standardization international standard in 1971 and published as ISO 3297 in 1975. ISO subcommittee TC 46/SC 9 is responsible for maintaining the standard; when a serial with the same content is published in more than one media type, a different ISSN is assigned to each media type. For example, many serials are published both in electronic media; the ISSN system refers to these types as electronic ISSN, respectively. Conversely, as defined in ISO 3297:2007, every serial in the ISSN system is assigned a linking ISSN the same as the ISSN assigned to the serial in its first published medium, which links together all ISSNs assigned to the serial in every medium.
The format of the ISSN is an eight digit code, divided by a hyphen into two four-digit numbers. As an integer number, it can be represented by the first seven digits; the last code digit, which may be 0-9 or an X, is a check digit. Formally, the general form of the ISSN code can be expressed as follows: NNNN-NNNC where N is in the set, a digit character, C is in; the ISSN of the journal Hearing Research, for example, is 0378-5955, where the final 5 is the check digit, C=5. To calculate the check digit, the following algorithm may be used: Calculate the sum of the first seven digits of the ISSN multiplied by its position in the number, counting from the right—that is, 8, 7, 6, 5, 4, 3, 2, respectively: 0 ⋅ 8 + 3 ⋅ 7 + 7 ⋅ 6 + 8 ⋅ 5 + 5 ⋅ 4 + 9 ⋅ 3 + 5 ⋅ 2 = 0 + 21 + 42 + 40 + 20 + 27 + 10 = 160 The modulus 11 of this sum is calculated. For calculations, an upper case X in the check digit position indicates a check digit of 10. To confirm the check digit, calculate the sum of all eight digits of the ISSN multiplied by its position in the number, counting from the right.
The modulus 11 of the sum must be 0. There is an online ISSN checker. ISSN codes are assigned by a network of ISSN National Centres located at national libraries and coordinated by the ISSN International Centre based in Paris; the International Centre is an intergovernmental organization created in 1974 through an agreement between UNESCO and the French government. The International Centre maintains a database of all ISSNs assigned worldwide, the ISDS Register otherwise known as the ISSN Register. At the end of 2016, the ISSN Register contained records for 1,943,572 items. ISSN and ISBN codes are similar in concept. An ISBN might be assigned for particular issues of a serial, in addition to the ISSN code for the serial as a whole. An ISSN, unlike the ISBN code, is an anonymous identifier associated with a serial title, containing no information as to the publisher or its location. For this reason a new ISSN is assigned to a serial each time it undergoes a major title change. Since the ISSN applies to an entire serial a new identifier, the Serial Item and Contribution Identifier, was built on top of it to allow references to specific volumes, articles, or other identifiable components.
Separate ISSNs are needed for serials in different media. Thus, the print and electronic media versions of a serial need separate ISSNs. A CD-ROM version and a web version of a serial require different ISSNs since two different media are involved. However, the same ISSN can be used for different file formats of the same online serial; this "media-oriented identification" of serials made sense in the 1970s. In the 1990s and onward, with personal computers, better screens, the Web, it makes sense to consider only content, independent of media; this "content-oriented identification" of serials was a repressed demand during a decade, but no ISSN update or initiative occurred. A natural extension for ISSN, the unique-identification of the articles in the serials, was the main demand application. An alternative serials' contents model arrived with the indecs Content Model and its application, the digital object identifier, as ISSN-independent initiative, consolidated in the 2000s. Only in 2007, ISSN-L was defined in the