Khor'Kova, N. G. books & textbook
Symmetries and Conservation Laws for Differential Equations of Mathematical Physics (Translations of Mathematical Monographs)
Bocharov, A. V. Chetverikov, V. N. Duzhin, S. V. Khor'Kova, N. G. Samokhin, A. V. Torkhov, Yu. N. Verbovetsky, A. M. Krasilshchik, I. S. Vinogradov, A. M.
Amer Mathematical Society /1999T Hardcover / 333 Pages
isbn-10: 082180958X / isbn-13: 9780821809587