@article{VUU_2013_3_a0,
     author = {E. I. Bravyi},
     title = {On unimprovable conditions of the solvability of the periodic problem for second order functional differential equations},
     journal = {Vestnik Udmurtskogo universiteta. Matematika, mehanika, kompʹ\^uternye nauki},
     pages = {3--19},
     publisher = {mathdoc},
     number = {3},
     year = {2013},
     language = {ru},
     url = {http://geodesic.mathdoc.fr/item/VUU_2013_3_a0/}
}