APA (7th ed.) Citation

Heppenheimer, T. A. (1997). Countdown: A history of space flight. John Wiley & Sons.

Chicago Style (17th ed.) Citation

Heppenheimer, T. A. Countdown: A History of Space Flight. New York, NY: John Wiley & Sons, 1997.

MLA (8th ed.) Citation

Heppenheimer, T. A. Countdown: A History of Space Flight. John Wiley & Sons, 1997.

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