1. Piecewise polynomial interpolation and approximation of functions;Birkhoff,1965
2. Variational study of nonlinear spline curves;Lee;SIAM Rev.,1973
3. On the computation of nonlinear spline functions;Malcolm;SIAM J. Numer. Anal.,1977
4. Properties of minimal energy splines;Brunnett,1992
5. A new characterization of plane elastica;Brunnett,1992