1. Apostol, T. M.,Mathematical Analysis, (Addison-Wesley, Reading, Mass., 1960), 559 pp.
2. Bellman, R. E. andKalaba, R. E.,Quasilinearization and Nonlinear Boundary-Value Problems (American Elsevier Publishing, New York 1965), 206 pp.
3. Birkhoff, G., Schultz, M. H., andVarga, R. S.,Piecewise Hermite Interpolation in One and Two Variables with Applications to Partial Differential Equations, Numer. Math.11, 232–256 (1968).
4. Ciarlet, P. G., Schultz, M. H., andVarga, R. S.,Numerical Methods of High-Order Accuracy for Nonlinear Boundary Value Problems, I:One dimensional problem, Numer. Math.9, 394–430 (1967).
5. Collatz, L.,The Numerical Treatment of Differential Equations, 3rd ed. (Springer, Berlin-Göttingen-Heidelberg 1960), 568 pp.