APA aipamena

World Resources Institute. (1991). The ... information please environmental almanac. Houghton Mifflin Co.

Chicago Style aipamena

World Resources Institute. The ... Information Please Environmental Almanac. Boston: Houghton Mifflin Co, 1991.

MLA aipamena

World Resources Institute. The ... Information Please Environmental Almanac. Houghton Mifflin Co, 1991.

Kontuz: berrikusi erreferentzia hauek erabili aurretik.