Ongpin, R. (1991). An entrepreneur never retires / Rafael Ongpin. Manila Chronicle.
Cita Chicago (17th ed.)Ongpin, Rafael. "An Entrepreneur Never Retires / Rafael Ongpin." Manila Chronicle 1991.
Cita MLA (9th ed.)Ongpin, Rafael. "An Entrepreneur Never Retires / Rafael Ongpin." Manila Chronicle, 1991.
Atenció: Aquestes cites poden no estar 100% correctes.