توثيق جمعية علم النفس الأمريكية APA (الطبعة السابعة)

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.

توثيق أسلوب شيكاغو (الطبعة السابعة عشر)

Gruber, Howard E., و 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.

توثيق جمعية اللغة المعاصرة MLA (الطبعة الثامنة)

Gruber, Howard E., و 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.