Dyfyniad APA
Ginsburg, H., & Opper, S. (1979). Piaget's theory of intellectual development (2d ed.). Prentice-Hall.
Dyfyniad Arddull Chicago
Ginsburg, Herbert, and Sylvia Opper. Piaget's Theory of Intellectual Development. 2d ed. Englewood Cliffs, N.J.: Prentice-Hall, 1979.
Dyfyniad MLA
Ginsburg, Herbert, and Sylvia Opper. Piaget's Theory of Intellectual Development. 2d ed. Prentice-Hall, 1979.
Rhybudd: Mae'n bosib nad yw'r dyfyniadau hyn bob amser yn 100% cywir.