APA (7e ed.) Bronvermelding

Não informado. (1974). Coal and Energy Quarterly. National Coal Board.

Chicago (17e ed.) Bronvermelding

Não informado. Coal and Energy Quarterly. London: National Coal Board, 1974.

MLA (8e ed.) Bronvermelding

Não informado. Coal and Energy Quarterly. National Coal Board, 1974.

Let op: Deze citaties zijn niet altijd 100% accuraat.