@conference {215,
	title = {On normals and control nets},
	booktitle = {Mathematics of Surfaces XI},
	year = {2005},
	publisher = {Springer-Verlag},
	organization = {Springer-Verlag},
	author = {Ingo Ginkel and J{\"o}rg Peters and Georg Umlauf},
	editor = {R.~Martin and H.~Bez and M.~Sabin pages = 233-239}
}
