APA (7th ed.) Zitazioa

Beard, R. M. (2006). An outline of Piaget's development psychology. Routledge.

Chicago Style (17th ed.) Zitazioa

Beard, Ruth M. An Outline of Piaget's Development Psychology. London: Routledge, 2006.

MLA (9th ed.) Zitazioa

Beard, Ruth M. An Outline of Piaget's Development Psychology. Routledge, 2006.