@conference {19841,
	title = {Normalising geometrical constructions: A context for the generation of meanings for ratio and proportion},
	booktitle = {Proceedings of the 28th Conference of the International Group for the Psychology of Mathematics Education (PME 28)},
	volume = {4},
	year = {2004},
	pages = {65-72},
	address = {Bergen, Norway},
	author = {G Psycharis and C Kynigos},
	editor = {M J H{\o}ines and A B Fuglestad}
}
