Cita APA (7th ed.)

Natividad, N. M. (1974). Soil survey of Abra province, Philippines: A reconnaissance soil survey. Government Printing Office.

Cita Chicago (17th ed.)

Natividad, Narciso M. Soil Survey of Abra Province, Philippines: A Reconnaissance Soil Survey. Manila: Government Printing Office, 1974.

Cita MLA (9th ed.)

Natividad, Narciso M. Soil Survey of Abra Province, Philippines: A Reconnaissance Soil Survey. Government Printing Office, 1974.