1. An Introduction to Gröbner Bases;Adams,1994
2. Applications of Group-Theoretical Methods in Hydrodynamics;Andreev,1998
3. Ueber Flachentransformationen;Bäcklund;Math. Ann.,1876
4. Gauge Theory and Variational Principles;Bleecker,1981
5. Exterior Differential Systems;Bryant,1991