Steyn, Wynand Jacobus Van der Merwe; Van Niekerk, Handre; Jacobs, Wietsche M.G.(Southern African Alliance for Sport Science, Physical Education and Recreation, 2014)
Mahlaba, Jabulani S.; Kearsley, Elsabe P.; Kruger, Richard A.(University of Kentucky Center for Applied Energy Research and the American Coal Ash Association, 2012)