@Article{jue:11b,
  author = {B. Bastl and B. J\"uttler and 
            M. L\'avi\v{c}ka and J. Schicho and Z. \v{S}\'{\i}r},
  title =  {Spherical quadratic {B}\'ezier triangles with chord
            lengths parameterization and tripolar coordinates
            in space},
  journal = {Computer Aided Geometric Design},
  volume = {28},
  year =  {2011},
  pages = {127-134},
  DOI = {doi:10.1016/j.cagd.2010.11.001}
}