APA (7th ed.) Zitazioa
Villarreal, O. (1999). Hotel and catering services: Resource file level 1 (1a. ed.). Macmillan.
Chicago Style (17th ed.) Zitazioa
Villarreal, Omar. Hotel and Catering Services: Resource File Level 1. 1a. ed. Buenos Aires: Macmillan, 1999.
MLA (9th ed.) Zitazioa
Villarreal, Omar. Hotel and Catering Services: Resource File Level 1. 1a. ed. Macmillan, 1999.
Kontuz: berrikusi erreferentzia hauek erabili aurretik.