Gaya APA

Cent., I, O, &, G, E. (1967). Exploration and economics of the petroleum industry volume 4. (1967). : Houston: Gulf publishing company,.

Gaya MLA

Cent., Inter., Oil, &, Gas, Educat.. "Exploration and economics of the petroleum industry volume 4.". 1967 : Houston: Gulf publishing company,, 1967. Text.