共 50 条
- [1] NONFACTORIZABLE SEPARABLE SYSTEMS AND HIGHER-ORDER SYMMETRIES OF THE DIRAC OPERATOR PROCEEDINGS OF THE ROYAL SOCIETY OF LONDON SERIES A-MATHEMATICAL PHYSICAL AND ENGINEERING SCIENCES, 1990, 428 (1874): : 229 - 249
- [3] HYPOELLIPTICITY OF 2ND-ORDER DIFFERENTIAL OPERATOR VESTNIK MOSKOVSKOGO UNIVERSITETA SERIYA 1 MATEMATIKA MEKHANIKA, 1985, (06): : 96 - 99
- [8] THE EXISTENCE OF ADJOINT FUNCTIONS OF A 2ND-ORDER OPERATOR DOKLADY AKADEMII NAUK SSSR, 1982, 262 (05): : 1036 - 1039