@incollection{Morken-91-circles,
  mrnumber = {MR1123755},
  author = {M{\o}rken, Knut},
  mrclass = {65D17},
  booktitle = {Curves and surfaces (Chamonix-Mont-Blanc, 1990)},
  address = {Boston, MA},
  title = {Best approximation of circle segments by quadratic {B}\'ezier
           curves},
  publisher = {Academic Press},
  year = {1991},
  pages = {331--336},
}