1. A. A. Ligun, ?On a property of interpolation spline functions,? Ukr. Mat. Zh.,32, No. 4, 507?514 (1980).
2. I. A. Pakhnutov, ?Convergence of splines with supplementary nodes,? Vychisl. Sistemy, No. 72, 96?129 (1975).
3. A. A. Ligun and V. F. Storchai, ?On the best choice of nodes for approximation of functions by local Hermite splines,? Ukr. Mat. Zh.,32, No. 6, 814?820 (1980).
4. V. L. Velikin, ?Hermite splines and connected quadrature formulas for certain classes of differentiable functions,? Izv. Vyssh. Uchebn. Zaved., Mat., No. 5, 15?18 (1976).
5. J. H. Ahlberg, E. N. Nilson, and J. L. Walsh, The Theory of Splines and Their Applications, Academic Press, New York (1967).