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@article{DE_1968_4_4_a15, author = {A. G. Ramm}, title = {The principle of the limit amplitude}, journal = {Differencialʹnye uravneni\^a}, pages = {714--720}, publisher = {mathdoc}, volume = {4}, number = {4}, year = {1968}, language = {ru}, url = {http://geodesic.mathdoc.fr/item/DE_1968_4_4_a15/} }
A. G. Ramm. The principle of the limit amplitude. Differencialʹnye uravneniâ, Tome 4 (1968) no. 4, pp. 714-720. http://geodesic.mathdoc.fr/item/DE_1968_4_4_a15/