1. On integration of a class of linear partial differential equations by means of definite integrals;Lie;Arch Math,1881
2. Application of symmetry methods to partial differential equations;Bluman,2010
3. Contact geometry and nonlinear differential equations;Kushner,2007
4. Applications of Lie groups to differential equations;Olver,1986
5. Group analysis of differential equations;Ovsiannikov,1982