1. Vorotnikov, V.I. and Rumyantsev, V.V., Ustojchivost’ i upravlenie po chasti koordinat fazovogo vektora dinamicheskikh sistem: teoriya, metody i prilozheniya (Stability and Control with respect to a Part of the Phase Coordinates of Dynamic Systems: Theory, Methods, and Applications), Moscow: Scientific World, 2001.
2. Abramov, S.A. and Bronstein, M., Solving linear systems of differential and difference equations with respect to a part of the unknowns, Comput. Math. Math. Phys., 2006, vol. 46, no. 2, pp. 218–230.
3. Beckermann, M., Cheng, H., and Labahn, G., Fraction-free row reduction of matrices of Ore polynomials, J. Symbolic Computation, 2006, vol. 41, no. 5, pp. 513–543.
4. Barkatou, M., El Bacha, C., Labahn, G., and Pflugel, E., On simultaneous row and column reduction of higher-order linear differencial systems, J. Symbolic Computation, 2013, vol. 49, pp. 45–64.
5. van der Put, M. and Singer, M.F., Galois Theory of Linear Differential Equations, Berlin: Springer, 2003.