Não informado. (1975). Official bulletin. International Labour Office.
Chicago (17e ed.) BronvermeldingNão informado. Official Bulletin. Geneva, Suíça: International Labour Office, 1975.
MLA (8e ed.) BronvermeldingNão informado. Official Bulletin. International Labour Office, 1975.
Let op: Deze citaties zijn niet altijd 100% accuraat.