Jensen, H., Pyle, A., Zosh, J. M., Ebrahim, H. B., Zaragoza Scherman, A., Reunamo, J., & Hamre, B. K. (2019). Play facilitation: the science behind the art of engaging young children (white paper). The LEGO Foundation, DK.
Dansky JL, Silverman I. Effects of play on associative fluency in preschool-aged children. Dev Psychol. 1973;9(1):38–43