@article{DE_1990_26_9_a0,
     author = {M. U. Akhmetov and N. A. Perestyuk},
     title = {The comparison method for differential equations with impulse action},
     journal = {Differencialʹnye uravneni\^a},
     pages = {1475--1483},
     publisher = {mathdoc},
     volume = {26},
     number = {9},
     year = {1990},
     language = {ru},
     url = {http://geodesic.mathdoc.fr/item/DE_1990_26_9_a0/}
}