Beard, R. M. (1969). An outline of Piaget's developmental psychology for students and teachers. Basic Books.
Lua i Stíl Chicago (17ú heag.)Beard, Ruth Mary. An Outline of Piaget's Developmental Psychology for Students and Teachers. New York: Basic Books, 1969.
Lua MLA (9ú heag.)Beard, Ruth Mary. An Outline of Piaget's Developmental Psychology for Students and Teachers. Basic Books, 1969.
Rabhadh: Seans nach mbeach na luanna seo go hiomlán cruinn i ngach uile chás.