APA Format
World Health Organization (WHO) . (). Smallpox eradiation, TRS.393. : Geneva WHO 1968
MLA Format
World Health Organization (WHO) . Smallpox eradiation, TRS.393. : Geneva WHO 1968,
Australian/Harvard Format
World Health Organization (WHO) . . Smallpox eradiation, TRS.393. Geneva WHO 1968, 
Warning: These citations may not always be 100% accurate.