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@article{MMO_1970_21_a6, author = {G. I. \`Eskin}, title = {A conjugacy problem for equations of principal type with two independent variables}, journal = {Trudy Moskovskogo matemati\v{c}eskogo ob\^{s}estva}, pages = {245--292}, publisher = {mathdoc}, volume = {21}, year = {1970}, language = {ru}, url = {http://geodesic.mathdoc.fr/item/MMO_1970_21_a6/} }
G. I. Èskin. A conjugacy problem for equations of principal type with two independent variables. Trudy Moskovskogo matematičeskogo obŝestva, Trudy Moskovskogo Matematicheskogo Obshchestva, Tome 21 (1970), pp. 245-292. http://geodesic.mathdoc.fr/item/MMO_1970_21_a6/