Philippines (Republic). Office of the President. Presidential Economic Staff. (1967). Provincial profiles: Ilocos Sur. PES.
Cita Chicago (17th ed.)Philippines (Republic). Office of the President. Presidential Economic Staff. Provincial Profiles: Ilocos Sur. Manila: PES, 1967.
Cita MLA (9th ed.)Philippines (Republic). Office of the President. Presidential Economic Staff. Provincial Profiles: Ilocos Sur. PES, 1967.
Atenció: Aquestes cites poden no estar 100% correctes.