1. Nonlinear Programming—Analysis and Methods;Avriel,1976
2. Nonlinear Programming-Theory and Algorithms;Bazaraa,1979
3. Interpolation and Approximation;Davis,1963
4. A remark concerning perfect splines;Deboor;Bull. Amer. Math. Soc.,1974
5. Interpolation by quadratic splines;Demko;J. Approx. Theory,1978