?url_ver=Z39.88-2004&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Adissertation&rft.au=Kynigos%2C+Polychronis.&rft.aufirst=Polychronis.&rft.aulast=Kynigos&rft.degree=Doctoral&rft.date=1988&rft.inst=Institute+of+Education%2C+University+of+London&rft.tpages=576&rft.title=From+intrinsic+to+non-intrinsic+geometry+%3A+a+study+of+childrens+understandings+in+logo-based+microworlds.