Παραπομπή APA

Shechan, A. (1972). Purnell's discovering nature. Purnell.

Παραπομπή Chicago Style

Shechan, A. Purnell's Discovering Nature. London: Purnell, 1972.

Παραπομπή MLA

Shechan, A. Purnell's Discovering Nature. Purnell, 1972.