APA (7th ed.) Citation

Vilenkin, N. I. (1971). Combinatorics. Academic Press.

Chicago Style (17th ed.) Citation

Vilenkin, N. I︠A︡. Combinatorics. New York: Academic Press, 1971.

MLA (9th ed.) Citation

Vilenkin, N. I︠A︡. Combinatorics. Academic Press, 1971.