(2007). Penguin Yearbook 2008. penguin Groups.
Chicago Style aipamenaPenguin Yearbook 2008. New Delhi: penguin Groups, 2007.
MLA aipamenaPenguin Yearbook 2008. penguin Groups, 2007.
Kontuz: berrikusi erreferentzia hauek erabili aurretik.
(2007). Penguin Yearbook 2008. penguin Groups.
Chicago Style aipamenaPenguin Yearbook 2008. New Delhi: penguin Groups, 2007.
MLA aipamenaPenguin Yearbook 2008. penguin Groups, 2007.