@book {RicKor-CPIG-2001,
	title = {Cinderella {\textendash} Programa interactivo di Geometria},
	year = {2001},
	note = {Portuguese translation.},
	publisher = {CMAFUL},
	organization = {CMAFUL},
	address = {Lisbon},
	keywords = {software},
	url = {http://cinderella.lmc.fc.ul.pt},
	author = {Richter-Gebert, J{\"u}rgen and Kortenkamp, Ulrich H.}
}
