APA-referens (7:e uppl.)

Ginsburg, H., & Opper, S. (1969). Piaget's theory of intellectual development: An introduction. Prentice-Hall.

Chicago-referens (17:e uppl.)

Ginsburg, Herbert, och Sylvia Opper. Piaget's Theory of Intellectual Development: An Introduction. Englewood Cliffs, N.J.: Prentice-Hall, 1969.

MLA-referens (8:e uppl.)

Ginsburg, Herbert, och Sylvia Opper. Piaget's Theory of Intellectual Development: An Introduction. Prentice-Hall, 1969.