Não informado. (1959). Copper abstracts. Copper Development Association.
Chicagoスタイル(17版)引用形式Não informado. Copper Abstracts. London: Copper Development Association, 1959.
MLA(8版)引用形式Não informado. Copper Abstracts. Copper Development Association, 1959.
警告: この引用は必ずしも正確ではありません.