Philippines (Republic). Government Service Insurance System. (1970). Basic reference manual. [s.n.].
Cita Chicago (17th ed.)Philippines (Republic). Government Service Insurance System. Basic Reference Manual. Manila: [s.n.], 1970.
Cita MLA (9th ed.)Philippines (Republic). Government Service Insurance System. Basic Reference Manual. [s.n.], 1970.
Atenció: Aquestes cites poden no estar 100% correctes.