Potgieter, Marietjie; Rogan, John M.; Howie, Sarah J.(Southern African Association for Research in Mathematics, Science and Technology Education, 2005)
Hattingh, Annemarie; Rogan, John M.; Aldous, Colleen; Howie, Sarah J.; Venter, Elsie(Southern African Association for Research in Mathematics, Science and Technology Education, 2005)