@book{97480,
	author = {Sierpinska, Anna. and ebrary, Inc.},
	title = {Understanding in mathematics},
	publisher = {Falmer,},
	year = {1994.},
	series = {Studies in mathematics education series ;},
	address = {London ;},
	url = {http://site.ebrary.com/lib/rucke/Doc?id=10096967}
}