Cita APA (7th ed.)

Callen, P. W. (1988). Ultrasonography in obstetrics and Gynecology.

Cita Chicago (17th ed.)

Callen, Peter W. Ultrasonography in Obstetrics and Gynecology. 1988.

Cita MLA (9th ed.)

Callen, Peter W. Ultrasonography in Obstetrics and Gynecology. 1988.

Atenció: Aquestes cites poden no estar 100% correctes.