APA Format
World Health Organization (WHO) . (). Intestinal protozoan and helminthic infections, TRS.666. : Geneva WHO 1981
MLA Format
World Health Organization (WHO) . Intestinal protozoan and helminthic infections, TRS.666. : Geneva WHO 1981,
Australian/Harvard Format
World Health Organization (WHO) . . Intestinal protozoan and helminthic infections, TRS.666. Geneva WHO 1981, 
Warning: These citations may not always be 100% accurate.