@conference {19804,
	title = {Teachers{\textquoteright} attempts to address both mathematical challenge and differentiation in whole class discussion},
	booktitle = {Proceedings of the Eleventh Congress of the European Society for Research in Mathematics Education},
	year = {2019},
	pages = {3738-3745},
	publisher = {Freudenthal Group \& Freudenthal Institute, Utrecht University and ERME},
	organization = {Freudenthal Group \& Freudenthal Institute, Utrecht University and ERME},
	address = {Utrecht, the Netherlands},
	author = {G Psycharis and D Potari and C Triantafillou and T Zachariades},
	editor = {U T Jankvist and M van den Heuvel-Panhuizen and M Veldhuis}
}
