Cita APA (7a ed.)

Callen, P. W. (1988). Ultrasonography in obstetrics and Gynecology (2.ed.). Saunders Company.

Cita Chicago Style (17a ed.)

Callen, Peter W. Ultrasonography in Obstetrics and Gynecology. 2.ed. Philadelphia: Saunders Company, 1988.

Cita MLA (9a ed.)

Callen, Peter W. Ultrasonography in Obstetrics and Gynecology. 2.ed. Saunders Company, 1988.