@Article{jue:07f,    
  author = 	 {M.\ Aigner and Z. \v{S}\'{\i}r and B. J\"uttler},
  title = 	 {Evolution based least--squares fitting using {P}ythagorean hodograph spline curves},
  journal = 	 {Comp. Aided Geom. Design},
  volume = {24},
  year = 	 {2007},
  pages = {310--322}
}