1. Géométrie Différentielle et Méchnique Analytique;Godbillon,1969
2. Differential geometry and Lagrangian mechanics with constraints;Verskik;Dokl. Akad. Nauk SSSR,1972
3. On the conditions for the existence of the Chaplygin reducing factor;Iliyev;Prikl. Mat. Mekh.,1985
4. On existence of an integral invariant of smooth dynmic systems;Kozlov;Prikl. Mat. Mekh.,1987
5. Studies in the Dynamics of Non-Holonomic Systems;Chaplygin,1949