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@article{DE_1970_6_1_a0, author = {A. V. Bitsadze}, title = {On the theory of equations of mixed type}, journal = {Differencialʹnye uravneni\^a}, pages = {3--6}, publisher = {mathdoc}, volume = {6}, number = {1}, year = {1970}, language = {ru}, url = {http://geodesic.mathdoc.fr/item/DE_1970_6_1_a0/} }
A. V. Bitsadze. On the theory of equations of mixed type. Differencialʹnye uravneniâ, Tome 6 (1970) no. 1, pp. 3-6. http://geodesic.mathdoc.fr/item/DE_1970_6_1_a0/