Cita APA (7th ed.)

CALLEN, P. W. (2000). Ultrasonography in obstetrics and gynecology.-- ed.4. W.B. Saunders Company.

Cita Chicago (17th ed.)

CALLEN, Peter W. Ultrasonography in Obstetrics and Gynecology.-- Ed.4. Philadelphia: W.B. Saunders Company, 2000.

Cita MLA (9th ed.)

CALLEN, Peter W. Ultrasonography in Obstetrics and Gynecology.-- Ed.4. W.B. Saunders Company, 2000.