@conference {19835,
	title = {Making sense of structural aspects of equations by using algebraic-like formalism},
	booktitle = {Proceedings of the Sixth Congress of the European Society for Research in Mathematics Education (CERME 6)},
	year = {2009},
	pages = {1419-1428},
	address = {Lyon, France},
	author = {F Moustaki and G Psycharis and C Kynigos},
	editor = {V Durand-Guerrier and S Soury-Lavergne and F Arzarello}
}
