APA Format
World Health Organization (WHO) . (). Biology of fertility control by periodic abstinence, report of a WHO Scientific Group Geneva: WHO, 1967.. :
MLA Format
World Health Organization (WHO) . Biology of fertility control by periodic abstinence, report of a WHO Scientific Group Geneva: WHO, 1967.. : ,
Australian/Harvard Format
World Health Organization (WHO) . . Biology of fertility control by periodic abstinence, report of a WHO Scientific Group Geneva: WHO, 1967.. , 
Warning: These citations may not always be 100% accurate.