@article {
pho75-phongshading,
	author = "Bui Tuong Phong",
	title = "Illumination for computer generated pictures",
	journal = "Communications of the ACM (CACM)",
	year = "1975",
	volume = "18",
	number = "6",
	pages = "311--317",
	month = "June",
	url = "http://portal.acm.org/citation.cfm?id=360839",
	lastchecked = "16.\,Oktober\,2007"
}