@article{Constantini-shape-preserving-ACM-2004,
  volume = {20},
  number = {1-3},
  mrnumber = {MR2055147 (2005a:65010)},
  issn = {1019-7168},
  author = {Costantini, Paolo and Pelosi, Francesca},
  mrclass = {65D10 (41A29 41A63)},
  fjournal = {Advances in Computational Mathematics},
  title = {Shape-preserving approximation of spatial data},
  pages = {25--51},
  journal = {Adv. Comput. Math.},
  year = {2004},
}