APA (7th ed.) Citation

Scientific American & Brandt, J. C. (1981). Comets. W.H. Freeman.

Chicago Style (17th ed.) Citation

Scientific American and John C. Brandt. Comets. San Francisco: W.H. Freeman, 1981.

MLA (9th ed.) Citation

Scientific American and John C. Brandt. Comets. W.H. Freeman, 1981.