APA (7th ed.) Citation

Berlin, I., Hardy, H., & Kelly, A. (1979). Russian thinkers. Penguin Books.

Chicago Style (17th ed.) Citation

Berlin, Isaiah, Henry Hardy, and Aileen Kelly. Russian Thinkers. New York: Penguin Books, 1979.

MLA (9th ed.) Citation

Berlin, Isaiah, et al. Russian Thinkers. Penguin Books, 1979.