@inproceedings{Prautzsch1992Approximate,
  Author = {Hartmut Prautzsch},
  Title = {Approximate C-blending with triangular cubic patches},
  Booktitle = {},
  Year = {1992},
  Note = {in: Computer Graphics and Mathematics, B. Falcidieno et al (eds.), Springer, 23-30
}
}