Hattingh, Annemarie; Van Loggerenberg-Hattingh, Annemarie; Aldous, Colleen; Rogan, John M.(Southern African Association for Research in Mathematics, Science and Technology Education, 2007)
Potgieter, Marietjie; Rogan, John M.; Howie, Sarah J.(Southern African Association for Research in Mathematics, Science and Technology Education, 2005)