@article{DAN_1989_308_5_a7,
     author = {A. V. Pokrovskii},
     title = {Global criteria for the existence of self-oscillatory regimes},
     journal = {Doklady Akademii Nauk},
     pages = {1057--1060},
     publisher = {mathdoc},
     volume = {308},
     number = {5},
     year = {1989},
     language = {ru},
     url = {http://geodesic.mathdoc.fr/item/DAN_1989_308_5_a7/}
}