APA (7th ed.) Citation

Sagan, C., & Shklovskii, I. (1966). Intelligent life in the universe. Dell Publishing.

Chicago Style (17th ed.) Citation

Sagan, Carl, and I.S Shklovskii. Intelligent Life in the Universe. New York: Dell Publishing, 1966.

MLA (9th ed.) Citation

Sagan, Carl, and I.S Shklovskii. Intelligent Life in the Universe. Dell Publishing, 1966.

Warning: These citations may not always be 100% accurate.