APA (7th ed.) Citation

Gabbe, S. G., Niebyl, J. R., & Simpson, J. L. (1991). Obstetrics: Normal and problem pregnancies (2nd ed.). Churchill Livingstone.

Chicago Style (17th ed.) Citation

Gabbe, Steven G., Jennifer R. Niebyl, and Joe Leigh Simpson. Obstetrics: Normal and Problem Pregnancies. 2nd ed. New York: Churchill Livingstone, 1991.

MLA (9th ed.) Citation

Gabbe, Steven G., et al. Obstetrics: Normal and Problem Pregnancies. 2nd ed. Churchill Livingstone, 1991.