A new method for the study of boundary value problems for linear and   quasi-linear systems of ODE
  The method is proposed for the study of many-point boundary value problems for systems of nonlinear ODE, by reducing them to special equivalent integral equations, and allows us [in contrast with the known method [1]] to consider boundary and initial value problems. Here we avoid the mechanism of Green's function whose construction is quite nontrivial, especially in case of many-point boundary value problems. The proposed algorithm [2, 3] makes it easier to write out the condition of unique solvability of such problems.   Key words: Boundary-value problems, Singular perturbation theory, Spectrum, Asymptotic behavior. 
Yu. A. Konyaev
math.CA