1. Application of Lie Groups to Differential Equations;Olver,1993
2. Symmetries and Differential Equations;Bluman,1989
3. Transformation Groups Applied to Mathematical Physics;Ibragimov,1985
4. Elementary Lie Group Analysis and Ordinary Differential Equations;Ibragimov,1999
5. Applied Exterior Calculus;G.B. Edelen,1985