1. The theory of splines and its applications;Ahlberg,1967
2. Bicubic spline interpolation;DeBoor;Jour. Math. and Phys.,1962
3. Linear estimation of nonstationary spatial phenomena;Delfiner,1975
4. Fonctions splines du type plaque mince en dimension 2;Duchon,1975
5. The theory of regionalized variables and its applications;Matheron,1971