Παραπομπή APA

(1976). Purnell's find out about wonders of the world. Purnell Books.

Παραπομπή Chicago Style

Purnell's Find Out About Wonders of the World. Maidenhead: Purnell Books, 1976.

Παραπομπή MLA

Purnell's Find Out About Wonders of the World. Purnell Books, 1976.