@article{DAN_1969_188_1_a11,
     author = {A. A. Il'yushin and G. S. Larionov and A. N. Filatov},
     title = {Averaging in systems of nonlinear integro-differential equations},
     journal = {Doklady Akademii Nauk},
     pages = {49--52},
     year = {1969},
     volume = {188},
     number = {1},
     language = {ru},
     url = {http://geodesic.mathdoc.fr/item/DAN_1969_188_1_a11/}
}