Cita APA (7th ed.)

Piaget, J., Gruber, H. E., & Voneche, J. J. (1977). The essential Piaget. Basic Books.

Cita Chicago (17th ed.)

Piaget, Jean, Howard E. Gruber, i J. Jacques Voneche. The Essential Piaget. New York: Basic Books, 1977.

Cita MLA (9th ed.)

Piaget, Jean, et al. The Essential Piaget. Basic Books, 1977.