@article{MZM_2009_85_3_a6,
     author = {B. S. Kalitin},
     title = {Instability of {Closed} {Invariant} {Sets} of {Semidynamical} {Systems.} {Method} of {Sign-Constant} {Lyapunov} {Functions}},
     journal = {Matemati\v{c}eskie zametki},
     pages = {382--394},
     publisher = {mathdoc},
     volume = {85},
     number = {3},
     year = {2009},
     language = {ru},
     url = {http://geodesic.mathdoc.fr/item/MZM_2009_85_3_a6/}
}