Philippines. National Economic and Development Authority. Regional Development Council, Region I. (1976). Demographic profile on Region I: A study on population growth, composition and employment. The Council.
Cita Chicago (17th ed.)Philippines. National Economic and Development Authority. Regional Development Council, Region I. Demographic Profile on Region I: A Study on Population Growth, Composition and Employment. San Fernando, La Union: The Council, 1976.
Cita MLA (9th ed.)Philippines. National Economic and Development Authority. Regional Development Council, Region I. Demographic Profile on Region I: A Study on Population Growth, Composition and Employment. The Council, 1976.
Atenció: Aquestes cites poden no estar 100% correctes.