APA (7th ed.) Citation

Thorpy, M. J., & Yager, J. (1991). The encyclopedia of sleep and sleep disorders / Michael J. Thorpy and Jan Yager. Facts on File.

Chicago Style (17th ed.) Citation

Thorpy, Michael J., and Jan Yager. The Encyclopedia of Sleep and Sleep Disorders / Michael J. Thorpy and Jan Yager. New York: Facts on File, 1991.

MLA (9th ed.) Citation

Thorpy, Michael J., and Jan Yager. The Encyclopedia of Sleep and Sleep Disorders / Michael J. Thorpy and Jan Yager. Facts on File, 1991.

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