APA Format
World Health Organization (WHO) . (). Nongonococcal urethritis and other selected sexually transmitted diseases of public health importance, TRS.660. : Geneva WHO 1981
MLA Format
World Health Organization (WHO) . Nongonococcal urethritis and other selected sexually transmitted diseases of public health importance, TRS.660. : Geneva WHO 1981,
Australian/Harvard Format
World Health Organization (WHO) . . Nongonococcal urethritis and other selected sexually transmitted diseases of public health importance, TRS.660. Geneva WHO 1981, 
Warning: These citations may not always be 100% accurate.