APA (7th ed.) Citation

Asimov, I., Martin, G. R. R., & Greenberg, M. H. (1983). The Science fiction weight-loss book. Crown.

Chicago Style (17th ed.) Citation

Asimov, Isaac, George R. R. Martin, and Martin Harry Greenberg. The Science Fiction Weight-loss Book. New York: Crown, 1983.

MLA (9th ed.) Citation

Asimov, Isaac, et al. The Science Fiction Weight-loss Book. Crown, 1983.