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@article{MZM_1968_4_1_a12, author = {N. V. Medvedev}, title = {An~existence principle for a~periodic solution of a~differential equation in {Banach} space}, journal = {Matemati\v{c}eskie zametki}, pages = {105--111}, publisher = {mathdoc}, volume = {4}, number = {1}, year = {1968}, language = {ru}, url = {http://geodesic.mathdoc.fr/item/MZM_1968_4_1_a12/} }
N. V. Medvedev. An~existence principle for a~periodic solution of a~differential equation in Banach space. Matematičeskie zametki, Tome 4 (1968) no. 1, pp. 105-111. http://geodesic.mathdoc.fr/item/MZM_1968_4_1_a12/