1. Hamiltonian structure of Sato's hierarchy of KP equations and a coadjoint orbit of a certain formal Lie group;Watanabe;Lett. Math. Phys.,1983
2. Degenerative dispersion laws, motion invariants, and kinetic equations;Zakharov;Physica,1980
3. Hamilton structure of the Kadomtsev-Petviashvili type equations;Reyman;Zap. Nauchni Sem. LOMI,1984
4. Symmetries of the higher-order KP equations;Case;J. Math. Phys.,1985
5. Fractional powers of operators and Hamiltonian systems;Gelfand;Funkz. Anal. Jego Prilozh,1976