APA (7th ed.) Citation

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

Chicago Style (17th ed.) Citation

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

MLA (9th ed.) Citation

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