APA (7e ed.) Bronvermelding

Não informado. (1970). Copper Abstracts. Copper Development Association.

Chicago (17e ed.) Bronvermelding

Não informado. Copper Abstracts. London: Copper Development Association, 1970.

MLA (8e ed.) Bronvermelding

Não informado. Copper Abstracts. Copper Development Association, 1970.

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