Tsebe, K.B., and R.L. van Niekerk. 2021. “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 (2):192-201. https://doi.org/10.37597/ajphes.2021.27.2.5.