1. L. V. Ovsyannikov, Group Analysis of
Differential Equations (Nauka, Moscow, 1978; Academic Press, New York etc.,
1982).
2. N. Kh. Ibragimov, Transformation Groups
Applied to Mathematical Physics (Nauka, Moscow, 1983; Reidel Publishing Company,
Dordrecht–Boston–Lancaster, 1985).
3. P. J. Olver, Applications of Lie Groups to
Differential Equations (Springer, New York, 1986; Mir, Moscow,
1989).
4. I. S. Krasil’shchik (ed.) and A. M. Vinogradov (ed.), Symmetries and Conservation Laws for Differential Equations of Mathematical
Physics (Faktorial, Moscow, 1997; AMS, Providence, RI; 1999).
5. A. F. Sidorov, V. P. Shapeev, and N. N. Yanenko, Method of Differential Constraints and Its Applications in Gas
Dynamics (Nauka, Novosibirsk, 1984) [in Russian].