de Villiers, Michael, University of KwaZulu-Natal, South Africa

• Vol 32, No 2 (2011) - Original Research
  An instrumental approach to modelling the derivative in Sketchpad
  Abstract  HTML  EPUB  XML  PDF
• Issue 63 (2006) - Original Research
  A generalisation of the Spieker circle and Nagel line
  Abstract  PDF
• Issue 62 (2005) - Original Research
  A generalisation of the nine-point circle and Euler line
  Abstract  PDF