Lotriet, H.H. (Hugo H.); Matthee, Machdel C.; Mazanderani, Fadhila(Department of Knowledge and Information Management, University of Johannesburg, 2009-03)
Lotriet, H.H. (Hugo H.); Matthee, Machdel C.; Alexander, Patricia Margaret(Southern African Association for Research in Mathematics, Science and Technology Education, 2011)