Cita APA (7a ed.)

Eastman, N., & Hellman, L. M. (1961). Williams Obstetrics (12.ed.). Appleton-Century-Croffts.

Cita Chicago Style (17a ed.)

Eastman, Nicholson, y Louis M. Hellman. Williams Obstetrics. 12.ed. New York: Appleton-Century-Croffts, 1961.

Cita MLA (9a ed.)

Eastman, Nicholson, y Louis M. Hellman. Williams Obstetrics. 12.ed. Appleton-Century-Croffts, 1961.