Northern Nigeria (Nigeria). Ministry of Health. Annual report of the Ministry of Health, Northern Nigeria. Govt. Printer.
Chicago-referens (17:e uppl.)Northern Nigeria (Nigeria). Ministry of Health. Annual Report of the Ministry of Health, Northern Nigeria. Kaduna: Govt. Printer.
MLA-referens (8:e uppl.)Northern Nigeria (Nigeria). Ministry of Health. Annual Report of the Ministry of Health, Northern Nigeria. Govt. Printer.
Varning: dessa hänvisningar är inte alltid fullständigt riktiga.