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@article{DE_1989_25_10_a3, author = {V. G. Zadorozhniy}, title = {Second-order differential equations in variational derivatives}, journal = {Differencialʹnye uravneni\^a}, pages = {1679--1683}, publisher = {mathdoc}, volume = {25}, number = {10}, year = {1989}, language = {ru}, url = {http://geodesic.mathdoc.fr/item/DE_1989_25_10_a3/} }
V. G. Zadorozhniy. Second-order differential equations in variational derivatives. Differencialʹnye uravneniâ, Tome 25 (1989) no. 10, pp. 1679-1683. http://geodesic.mathdoc.fr/item/DE_1989_25_10_a3/