Justification of the averaging method for multipoint boundary value problems for a class of functional-differential equations with maximums. S. D. Milusheva; D. D. Bainov — 1986 Collectanea Mathematica
Application of the averaging method for the solution of boundary problems for ordinary differential and integro-differential equations Bainov, D. D.; Milusheva, S. D. — 1979 Equadiff IV