Callen, P. W. (1988). Ultrasonography in obstetrics and Gynecology.
芝加哥风格引文Callen, Peter W. Ultrasonography in Obstetrics and Gynecology. 1988.
MLA引文Callen, Peter W. Ultrasonography in Obstetrics and Gynecology. 1988.
警告：这些引文格式不一定是100％准确.
APA引文