1. Brish,N.I., On Boundary Value Problems for the Equation εy″=f(x, y, y′) for small ε, Dokl. Akad. Nauk SSSR 95 (1954), 429–432.
2. Hebets,P. and M.Laloy, Étude de problèmes aux limités par la méthode des suret sous-solutions, Lecture notes, Catholic University of Louvain, Belgium (1974).
3. Bernfeld,S. and V.Lakshmikantham, An Introduction to Nonlinear Boundary Value Problems, Academic Press, New York, (1974).
4. Boglaev, Yu.B., The two-point problem for a class of ordinary differential equations with a small parameter coefficient of the derivative, USST Comp. Math. and Math. Phys. 10 (1970), 4, 191–204.
5. Chang,K.W. and F.A.Howes, Nonlinear Singular Perturbation Phenomena, Springer-Verlag Pub. (in press)