APA (7th ed.) Zitazioa
(1987). Digital Elevation Models. United States, Dept. of the Interior, U.S. Geolog. Survey.
Chicago Style (17th ed.) Zitazioa
Digital Elevation Models. Reston, Va: United States, Dept. of the Interior, U.S. Geolog. Survey, 1987.
MLA (9th ed.) Zitazioa
Digital Elevation Models. United States, Dept. of the Interior, U.S. Geolog. Survey, 1987.
Kontuz: berrikusi erreferentzia hauek erabili aurretik.