Tsebe, K.B., and R.L. van Niekerk. “Effect of a 7-Week Mindfulness-Acceptance-Commitment Intervention Programme on Mental Toughness: An Experimental Study of Male League Softball Players”. African Journal for Physical Activity and Health Sciences 27, no. 2 (August 13, 2021): 192–201. Accessed November 12, 2026. https://www.ajol.info/index.php/ajpherd/article/view/212556.