APA aipamena

World Resources Institute. (1993). The 1993 Information please environmental almanac. Houghton Mifflin Co.

Chicago Style aipamena

World Resources Institute. The 1993 Information Please Environmental Almanac. Boston: Houghton Mifflin Co, 1993.

MLA aipamena

World Resources Institute. The 1993 Information Please Environmental Almanac. Houghton Mifflin Co, 1993.

Kontuz: berrikusi erreferentzia hauek erabili aurretik.