Ngololo, E.N. (Elizabeth Ndeukumwa); Howie, Sarah J.; Plomp, Tjeerd(Southern African Association for Research in Mathematics, Science and Technology Education, 2012)
Du Toit, Pieter Hertzog; De Boer, Ann-Louise; Bothma, T.J.D. (Theodorus Jan Daniel); Scheepers, M.D. (Maria Detken)(Suid Afrikaanse Akademie vir Wetenskap & Kuns, 2012)