@article{DAN_1968_178_1_a11,
     author = {M. M. Khapaev},
     title = {Instability under constantly acting perturbations},
     journal = {Doklady Akademii Nauk},
     pages = {47--50},
     publisher = {mathdoc},
     volume = {178},
     number = {1},
     year = {1968},
     language = {ru},
     url = {http://geodesic.mathdoc.fr/item/DAN_1968_178_1_a11/}
}