Cita APA (7a ed.)

Ginsburg, H., & Opper, S. (1998). Pïaget's theory of intellectual development. UNESCO.

Cita Chicago Style (17a ed.)

Ginsburg, Herbert, y Sylvia Opper. Pïaget's Theory of Intellectual Development. París, Francia: UNESCO, 1998.

Cita MLA (9a ed.)

Ginsburg, Herbert, y Sylvia Opper. Pïaget's Theory of Intellectual Development. UNESCO, 1998.