Mogotsi, Isaac C.; Boon, J.A. (Johannes Anton); Fletcher, Lizelle(Department of Knowledge and Information Management, University of Johannesburg, 2011-11-25)
De Boer, Ann-Louise; Du Toit, Pieter Hertzog; Bothma, T.J.D. (Theodorus Jan Daniel)(Vaal Triangle Faculty of Northwest University in South Africa, 2015-11)