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@article{DE_1984_20_4_a21, author = {D. Kh. Safarov}, title = {Systems of second-order partial differential equations}, journal = {Differencialʹnye uravneni\^a}, pages = {716--719}, publisher = {mathdoc}, volume = {20}, number = {4}, year = {1984}, language = {ru}, url = {http://geodesic.mathdoc.fr/item/DE_1984_20_4_a21/} }
D. Kh. Safarov. Systems of second-order partial differential equations. Differencialʹnye uravneniâ, Tome 20 (1984) no. 4, pp. 716-719. http://geodesic.mathdoc.fr/item/DE_1984_20_4_a21/