1. Classification und Integration von gew�hnlichen Differentialgleichungen zwischenxy, die eine Gruppe von Transformationen gestatten
2. J. Krause and L. Michel, C.R. Acad. Sci. Paris 307, 905–910 (1988).
3. Symmetries of linear systems of second‐order ordinary differential equations
4. J. C. Ndogmo, ”Algebraic structure and maximal dimension of the symmetry algebra for arbitrary systems of odes,” arXiv:1606.08074 2016.
5. J. C. Ndogmo, ”Characterization of the class of canonical forms for systems of linear equations,” arXiv:1502.07164 2015.