Henrik Almegaard Anne Bagger Jens Gravesen Bert Jüttler Zbynek Sír Surfaces with Piecewise Linear Support Functions over Spherical Triangulations. 42-63 2007 conf/ima-ms/2007 IMA Conference on the Mathematics of Surfaces http://dx.doi.org/10.1007/978-3-540-73843-5_3 db/conf/ima-ms/ima-ms2007.html#AlmegaardBGJS07