Callen, P. W. (1988). Ultrasonography in obstetrics and Gynecology (2.ed.). Saunders Company.
Chicago Style aipamenaCallen, Peter W. Ultrasonography in Obstetrics and Gynecology. 2.ed. Philadelphia: Saunders Company, 1988.
MLA aipamenaCallen, Peter W. Ultrasonography in Obstetrics and Gynecology. 2.ed. Saunders Company, 1988.
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