1. English transl.: Functional Anal. Appl., 25, No. 3, 195–204 (19
2. B. A. Dubrovin and S. P. Novikov, “The Hamiltonian formalism of one-dimensional systems of hydrodynamic type and the Bogolyubov-Whitham averaging method,” Dokl. Akad. Nauk SSSR, 270, No. 4, 781–785 (1983);
3. English transl.: Soviet Math. Dokl., 27, 665–669 (19
4. English transl.: Russian Math. Surveys, 45, No. 3, 218–219 (19
5. F. Magri, “A simple model of the integrable Hamiltonian equation,” J. Math. Phys., 19, No. 5, 1156–1162 (197