Não informado. (1968). World Health Statistics Report. World Health Organization.
Chicago (17e ed.) BronvermeldingNão informado. World Health Statistics Report. Geneva, Suíça: World Health Organization, 1968.
MLA (8e ed.) BronvermeldingNão informado. World Health Statistics Report. World Health Organization, 1968.
Let op: Deze citaties zijn niet altijd 100% accuraat.