共 21 条
[11]
Goursat E., Leçons sur L’intégration des Équations aux Dérivées Partielles du Second Ordre à Deux Variables Indépendantes, 2, (1898)
[12]
Grayson M., The heat equation shrinks embedded plane curves to round points, J. Differential Geom, 26, pp. 285-314, (1987)
[13]
Krasilshchik I.S., Vinogradov A.M., Nonlocal symmetries and the theory of coverings: An addendum to Vinogradovs
[14]
Local symmetries and conservation laws, Acta Appl. Math, 2, pp. 79-96, (1984)
[15]
Lax P., Hyperbolic Systems of Conservation Laws and the Mathematical Theory of Shock Waves, CBMS-NSF Regional Conf. Ser. in Appl. Math, 11, (1973)
[16]
Lepage T., Sur certaines formes différentielles associées aux equations du type de Monge-Ampère provenant du
[17]
Calcul des Variations, Bull. Acad. Belgique Cl. Sci, 16, 5, pp. 1334-1352, (1930)
[18]
Mikhailov A.V., Shabat A.B., Sokolov V.V., The symmetry approach to classification of integrable systems, What Is Integrability?, pp. 115-184, (1991)
[19]
Olver P., Applications of Lie Groups to Differential Equations, 107, (1986)
[20]
Tsujishita T., On variation bicomplexes associated to differential equations, Osaka J. Math, 19, pp. 311-363, (1982)