Berg, K., Buresh, R., Parks, L., Kissinger, K., Karasek, D., Sinnett, A., Trehearn, T. Julkaisussa The Journal of Sports Medicine and Physical Fitness (2010)
Tharp, L., Berg, K., Latin, R. W., Stuberg, W. Julkaisussa Sports Medicine, Training and Rehabilitation (1997)