@article{Farin:1989:CCA,
  author = {Gerald Farin},
  title = {Curvature Continuity and Offsets for Piecewise Conics},
  journal = {ACM Transactions on Graphics},
  volume = {8},
  number = {2},
  pages = {89--99},
  month = apr,
  year = {1989},
}