Não informado. (1968). Petroleum Review. Institute of Petroleum.
Chicagoスタイル(17版)引用形式Não informado. Petroleum Review. London: Institute of Petroleum, 1968.
MLA(8版)引用形式Não informado. Petroleum Review. Institute of Petroleum, 1968.
警告: この引用は必ずしも正確ではありません.