Beard, R. M. (2006). An outline of Piaget's development psychology. Routledge.
Chicago Style (17. basım) AtıfBeard, Ruth M. An Outline of Piaget's Development Psychology. London: Routledge, 2006.
MLA (9th ed.) AtıfBeard, Ruth M. An Outline of Piaget's Development Psychology. Routledge, 2006.
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