@article{Seidel:1993:PFF,
  author = {Hans-Peter Seidel},
  title = {Polar Forms for Geometrically Continuous Spline Curves of Arbitrary Degree},
  journal = {ACM Transactions on Graphics},
  volume = {12},
  number = {1},
  pages = {1--34},
  month = jan,
  year = {1993},
}