1. C. Fitzgerald and L. L. Schumaker,A differential equations approach to interpolation at extremal points, J. Analyse Math,22 (1969), 117–134.
2. F. R. Gantmacher and M. G. Krein,Oscillatory Matrices and Kernels and Small Vibrations of Mechanical Systems, 2nd ed., Moscow (Russian), 1950.
3. R. S. Johnson,On monosplines of least deviation, Trans. Amer. Math. Soc.96 (1960), 458–477.
4. S. Karlin,Best quadrature and splines, J. Approximation. Theory,4 (1971), 59–90.
5. S. Karlin,The fundamental theorem of algebra for monosplines satisfying boundary conditions, appeared in Approximation with Special Emphasis on Spline Functions Academic Press, New York, N. Y., 1969.