A systematic construction of the Green's matrix for a second order,
self-adjoint matrix differential operator from the linearly independent
solutions of the corresponding homogeneous differential equation set is carried
out. We follow the general approach of extracting the Green's matrix from the
Green's matrix of the corresponding first order system. This construction is
required in the cases where the differential equation set cannot be turned to
an algebraic equation set via transform techniques.Comment: 19 page