@book{11647,
	author = {Hagen, Hans},
	title = {Curve and surface design},
	publisher = {Society For Industrial and Applied Mathematics},
	year = {1992},
	address = {Philadelphia },
	url = {https://www.libgen.is/book/index.php?md5=5D92B546DF7D9800547E62EABB648D35}
}