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@article{DE_1973_9_1_a11, author = {T. I. Lanina}, title = {Certain problems for equations of hyperbolic and mixed types}, journal = {Differencialʹnye uravneni\^a}, pages = {115--122}, publisher = {mathdoc}, volume = {9}, number = {1}, year = {1973}, language = {ru}, url = {http://geodesic.mathdoc.fr/item/DE_1973_9_1_a11/} }
T. I. Lanina. Certain problems for equations of hyperbolic and mixed types. Differencialʹnye uravneniâ, Tome 9 (1973) no. 1, pp. 115-122. http://geodesic.mathdoc.fr/item/DE_1973_9_1_a11/