Van Heerden, Cornelius Hendrik, 1957-; Van Heerden, Neels, 1957-; Green, M.; Van Tonder, Estelle(Africa Association for Health, Physical Education, Recreation, Sport and Dance, 2007-12)
Rensburg, Ronel S.; De Beer, Estelle(Unit for Community Communication, Department of Communication and Information Studies, University of the Free State, 2011-11)