APA (7th ed.) Zitazioa

Kurtz. A Year of Iowa Nature. University of Iowa Press.

Chicago Style (17th ed.) Zitazioa

Kurtz. A Year of Iowa Nature. University of Iowa Press.

MLA (9th ed.) Zitazioa

Kurtz. A Year of Iowa Nature. University of Iowa Press.

Kontuz: berrikusi erreferentzia hauek erabili aurretik.