APA (7th ed.) Zitazioa
Poulsen, E. (2009). Smiling bears: A zookeeper explores the behavior and emotional life of bears. Greystone Books.
Chicago Style (17th ed.) Zitazioa
Poulsen, Else. Smiling Bears: A Zookeeper Explores the Behavior and Emotional Life of Bears. Vancouver: Greystone Books, 2009.
MLA (9th ed.) Zitazioa
Poulsen, Else. Smiling Bears: A Zookeeper Explores the Behavior and Emotional Life of Bears. Greystone Books, 2009.
Kontuz: berrikusi erreferentzia hauek erabili aurretik.