APA (7th ed.) Zitazioa
Sivard, R. L. (1981). World energy survey (2nd ed.). World Priorities.
Chicago Style (17th ed.) Zitazioa
Sivard, Ruth Leger. World Energy Survey. 2nd ed. Leesburg, Virginia: World Priorities, 1981.
MLA (9th ed.) Zitazioa
Sivard, Ruth Leger. World Energy Survey. 2nd ed. World Priorities, 1981.
Kontuz: berrikusi erreferentzia hauek erabili aurretik.