Petroleum Institute of the Philippines, Inc. (1971). Topics on the oil industry. s.n.
Lua i Stíl Chicago (17ú heag.)Petroleum Institute of the Philippines, Inc. Topics on the Oil Industry. [Manila: s.n, 1971.
Lua MLA (9ú heag.)Petroleum Institute of the Philippines, Inc. Topics on the Oil Industry. s.n, 1971.
Rabhadh: Seans nach mbeach na luanna seo go hiomlán cruinn i ngach uile chás.