@inproceedings{Prautzsch1992Is,
  Author = {Hartmut Prautzsch and Tim Gallagher},
  Title = {Is there a geometric variation diminishing property for B-spline or B surfaces?},
  Booktitle = {},
  Year = {1992},
  Note = {CAGD 9 119-124, T. Lyche, L.L. Schumaker (eds.) Academic Press 475-480
}
}