@article{IIMI_2015_2_a2,
     author = {E. I. Bravyi},
     title = {On positive periodic solutions of first order functional differential equations},
     journal = {Izvestiya Instituta Matematiki i Informatiki Udmurtskogo Gosudarstvennogo Universiteta},
     pages = {21--28},
     year = {2015},
     number = {2},
     language = {ru},
     url = {http://geodesic.mathdoc.fr/item/IIMI_2015_2_a2/}
}