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@article{DE_1969_5_4_a12, author = {B. P. Tkach}, title = {Periodic solution of systems of partial differential equations of neutral type}, journal = {Differencialʹnye uravneni\^a}, pages = {735--748}, publisher = {mathdoc}, volume = {5}, number = {4}, year = {1969}, language = {ru}, url = {http://geodesic.mathdoc.fr/item/DE_1969_5_4_a12/} }
B. P. Tkach. Periodic solution of systems of partial differential equations of neutral type. Differencialʹnye uravneniâ, Tome 5 (1969) no. 4, pp. 735-748. http://geodesic.mathdoc.fr/item/DE_1969_5_4_a12/