Cita APA (7th ed.)

(1972). Population map 1970: Cities and municipalities, Bicol region. [s.n.].

Cita Chicago (17th ed.)

Population Map 1970: Cities and Municipalities, Bicol Region. [Manila]: [s.n.], 1972.

Cita MLA (9th ed.)

Population Map 1970: Cities and Municipalities, Bicol Region. [s.n.], 1972.