1. Approximate symmetries of equations with a small parameter;Baikov;Mat Sb,1988
2. Symmetries and differential equations;Bluman,1989
3. Cheviakov AF. ::GeM:: – a module for symmetry and conservation law analysis. Retrieved October 24; 2010. .
4. Cheviakov AF. 2009, Description: GeM symbolic software package (version 0.31+) for general symmetry and conservation law analysis of differential equations. Retrieved October 24; 2010. .
5. GeM software package for computation of symmetries and conservation laws of differential equations;Cheviakov;Comput Phys Commun,2007