APA aipamena

(1972). Topography ; Bicol region. [s.n.].

Chicago Style aipamena

Topography ; Bicol Region. [Manila]: [s.n.], 1972.

MLA aipamena

Topography ; Bicol Region. [s.n.], 1972.

Kontuz: berrikusi erreferentzia hauek erabili aurretik.