(1976). Purnell's find out about wonders of the world. Purnell Books.
Chicago Style aipamenaPurnell's Find Out About Wonders of the World. Maidenhead: Purnell Books, 1976.
MLA aipamenaPurnell's Find Out About Wonders of the World. Purnell Books, 1976.
Kontuz: berrikusi erreferentzia hauek erabili aurretik.