Clark, Laura E., and Deborah J. Rhea. “The LiiNK Project®: Comparisons of Recess, Physical Activity, and Positive Emotional States in Grades K-2 Children”. International Journal of Child Health and Nutrition 6, no. 2 (May 24, 2017): 54–61. Accessed December 21, 2024. https://lifescienceglobal.com/pms/index.php/ijchn/article/view/4658.