APA

Downey M. W., American Association of Petroleum Geologists, . (2001). Petroleum provinces of the twenty-first century. Tulsa, Okla: The American Association of Petroleum Geologists.

Chicago

Downey Marlan W, American Association of Petroleum Geologists, . 2001. Petroleum provinces of the twenty-first century. Tulsa, Okla: The American Association of Petroleum Geologists.

Harvard

Downey M. W., American Association of Petroleum Geologists, . (2001). Petroleum provinces of the twenty-first century. Tulsa, Okla: The American Association of Petroleum Geologists.

MLA

Downey Marlan W, American Association of Petroleum Geologists, . Petroleum provinces of the twenty-first century. Tulsa, Okla: The American Association of Petroleum Geologists. 2001.