Cita APA (7th ed.)

(1972). Population and heirarchy of cities and municipalities: Bicol region. [s.n.].

Cita Chicago (17th ed.)

Population and Heirarchy of Cities and Municipalities: Bicol Region. [Manila]: [s.n.], 1972.

Cita MLA (9th ed.)

Population and Heirarchy of Cities and Municipalities: Bicol Region. [s.n.], 1972.