Philippine National Oil Company. (1973). Annual report. PNOC.
Cita Chicago (17th ed.)Philippine National Oil Company. Annual Report. [Makati, Metro Manila]: PNOC, 1973.
Cita MLA (9th ed.)Philippine National Oil Company. Annual Report. PNOC, 1973.
Atenció: Aquestes cites poden no estar 100% correctes.