1. J. H. Ahlberg, E. N. Nilson, and J. L. Walsh, The Theory of Splines and Their Applications, Academic Press, New York (1967).
2. R. Arcangeli, M. C. Lopez de Silanes, and J. J. Torrens, Multidimensional Minimizing Splines, Kluwer Academic publishers, Boston (2004).
3. M. Attea, Hilbertian Kernels and Spline Functions, North-Holland, Amsterdam (1992).
4. C. de Boor, “Best approximation properties of spline functions of odd degree,” J. Math. Mech., 12, 747–749 (1963).
5. C. de Boor, A Practical Guide to Splines, Springer, New York–Heidelberg–Berlin (1978).