@article{MZM_1970_8_2_a10, author = {V. V. Strygin}, title = {A theorem concerning the existence of periodic solutions of systems of differential equations with delayed arguments}, journal = {Matemati\v{c}eskie zametki}, pages = {229--234}, publisher = {mathdoc}, volume = {8}, number = {2}, year = {1970}, language = {ru}, url = {http://geodesic.mathdoc.fr/item/MZM_1970_8_2_a10/} }