APA (7th ed.) Citation

Shklovskiĭ, I. S., & Sagan, C. (1966). Intelligent life in the universe. Holden-Day.

Chicago Style (17th ed.) Citation

Shklovskiĭ, I. S., and Carl Sagan. Intelligent Life in the Universe. San Francisco: Holden-Day, 1966.

MLA (9th ed.) Citation

Shklovskiĭ, I. S., and Carl Sagan. Intelligent Life in the Universe. Holden-Day, 1966.

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