Cita APA (7th ed.)

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

Cita Chicago (17th ed.)

Ginsburg, Herbert, i Sylvia Opper. Piaget's Theory of Intellectual Development: An Introduction. New Jersey: Prentice Hall, 1969.

Cita MLA (9th ed.)

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