Cita APA (7a ed.)

Gruber, H. E., & Piaget, J. (1981). Darwin on man: A psychological study of scientific creativity / Howard E. Gruber. Foreword to the first ed. by Jean Piaget (2. ed.). Univ. of Chicago Press.

Cita Chicago Style (17a ed.)

Gruber, Howard E., y Jean Piaget. Darwin on Man: A Psychological Study of Scientific Creativity / Howard E. Gruber. Foreword to the First Ed. by Jean Piaget. 2. ed. Chicago: Univ. of Chicago Press, 1981.

Cita MLA (8a ed.)

Gruber, Howard E., y Jean Piaget. Darwin on Man: A Psychological Study of Scientific Creativity / Howard E. Gruber. Foreword to the First Ed. by Jean Piaget. 2. ed. Univ. of Chicago Press, 1981.