?url_ver=Z39.88-2004&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Adissertation&rft.au=Yaakub%2C+Baiduriah.&rft.aulast=Yaakub&rft.aufirst=Baiduriah.&rft.date=2003&rft.title=Graphing+calculators+and+the+zone+of+proximal+development+%3A+a+study+of+fourteen+year+old+Malaysian+students+development+of+graphical+concepts+with+technology&rft.tpages=493&rft.degree=Doctoral&rft.inst=Institute+of+Education%2C+University+of+London