APA (7th ed.) Citation

Piaget, J., Elkind, D., & Tenzer, A. (1968). Six psychological studies. University of London Press.

Chicago Style (17th ed.) Citation

Piaget, Jean, David Elkind, and Anita Tenzer. Six Psychological Studies. London: University of London Press, 1968.

MLA (9th ed.) Citation

Piaget, Jean, et al. Six Psychological Studies. University of London Press, 1968.

Warning: These citations may not always be 100% accurate.