@incollection{he2005ac,
  title={A C^1 globally interpolatory spline of arbitrary topology},
  author={He, Ying and Jin, Miao and Gu, Xianfeng and Qin, Hong},
  booktitle={3rd IEEE Workshop on Variational, Geometric, and Level Set Methods in Computer Vision (VLSM)},
  pages={295--306},
  year={2005},
  publisher={Springer}
}