APA (7th ed.) Citation

Bobev, P., Brückner, W., & Stoilov, S. (1977). Kaliakra. Sofia-Press.

Chicago Style (17th ed.) Citation

Bobev, Peter, Willi Brückner, and Stoimen Stoilov. Kaliakra. Sofia: Sofia-Press, 1977.

MLA (8th ed.) Citation

Bobev, Peter, et al. Kaliakra. Sofia-Press, 1977.