The integral representation of solutions to a boundary value problem on   the half-line for a system of linear ODEs with singularity of first kind
  We consider a problem of finding vanishing at infinity $C^1([0,\oo))$-solutions to non-homogeneous system of linear ODEs which has the pole of first order at $x=0$. The resonant case where the corresponding homogeneous problem has nontrivial solutions is of main interest. Under the conditions that the homogeneous system is exponentially dichotomic on $[1,\oo)$ and the residue of system's operator at $x=0$ does not have eigenvalues with real part 1, we construct the so called generalized Green function. We also establish conditions under which the main non-homogeneous problem can be reduced to the Noetherian one with nonzero index. 
Yulia Horishna, Igor Parasyuk, Lyudmyla Protsak