APA (7th ed.) Zitazioa

Gallup Management Journal. Gallup Poll News Service.

Chicago Style (17th ed.) Zitazioa

Gallup Management Journal. Gallup Poll News Service.

MLA (9th ed.) Zitazioa

Gallup Management Journal. Gallup Poll News Service.

Kontuz: berrikusi erreferentzia hauek erabili aurretik.