Philip James Bone was an English mandolinist and guitar player in the late 19th and early 20th centuries.
Philip J. Bone, from his book The Guitar and Mandolin.
Besides sheet music, Bone also sold musical instruments, as shown in this 1914 advertisement from the back of his book.
Johann Friedrich Franz Burgmüller, generally known as Friedrich Burgmuller was a German pianist and composer during the Romantic period. He is perhaps best known for his three collections of children's etudes for the piano, particularly his Op. 100 "25 Études faciles et progressives" for early intermediate students. The other two collections, for more advanced students, were Op. 105 and 109.
Johann Friedrich Franz Burgmüller from a lithograph, c.1840