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@article{MZM_1992_52_5_a8, author = {A. G. Kushner}, title = {Chaplygin and {Keldysh} normal forms of {Monge--Ampere} equations of variable type}, journal = {Matemati\v{c}eskie zametki}, pages = {63--67}, publisher = {mathdoc}, volume = {52}, number = {5}, year = {1992}, language = {ru}, url = {http://geodesic.mathdoc.fr/item/MZM_1992_52_5_a8/} }
A. G. Kushner. Chaplygin and Keldysh normal forms of Monge--Ampere equations of variable type. Matematičeskie zametki, Tome 52 (1992) no. 5, pp. 63-67. http://geodesic.mathdoc.fr/item/MZM_1992_52_5_a8/