APA Format
World Health Organization (WHO) . (). Partially halogenated chlorofluorocarbons (methane derivatives). : Geneva WHO 1991
MLA Format
World Health Organization (WHO) . Partially halogenated chlorofluorocarbons (methane derivatives). : Geneva WHO 1991,
Australian/Harvard Format
World Health Organization (WHO) . . Partially halogenated chlorofluorocarbons (methane derivatives). Geneva WHO 1991, 
Warning: These citations may not always be 100% accurate.