APA (7th ed.) Zitazioa

Political Risk Yearbook: United States Country Report. PRS Group, Inc.

Chicago Style (17th ed.) Zitazioa

Political Risk Yearbook: United States Country Report. PRS Group, Inc.

MLA (9th ed.) Zitazioa

Political Risk Yearbook: United States Country Report. PRS Group, Inc.

Kontuz: berrikusi erreferentzia hauek erabili aurretik.