Vassil Tzankov Tzankov was a Bulgarian geologist and paleontologist. He is best known for his work on Upper Cretaceous ammonites and bivalves. Tzankov was head of Bulgarian Geological Survey from 1941 until 1944. In 1945 he became docent and in 1947 - professor, and was appointed to the paleontology chair at Sofia University "St. Kliment Ohridski". In the late 1950s Tzankov organized the launch and became the first editor and one of the principal authors of the multi-volume treatise "Fossils of Bulgaria". Contributors to the treatise included leading Bulgarian specialists in the field. He served as deputy director of the Geological Institute at the Committee for Geology and Mineral Resources in the period 1960-1966. From 1967 to 1982 Tzankov also served as head of the Department of Paleontology with the Geological Institute at the Bulgarian Academy of Sciences. In 1967 he was elected as a corresponding member of the Bulgarian Academy of Sciences.

Sofia University "St. Kliment Ohridski" is a public research university in Sofia, Bulgaria. It is the oldest institution of higher education in Bulgaria.