@article{DE_2000_36_4_a22,
     author = {Yu. V. Usachev},
     title = {Bifurcation of invariant tori in a neighborhood of an equilibrium of a system of ordinary differential equations},
     journal = {Differencialʹnye uravneni\^a},
     pages = {569--571},
     publisher = {mathdoc},
     volume = {36},
     number = {4},
     year = {2000},
     language = {ru},
     url = {http://geodesic.mathdoc.fr/item/DE_2000_36_4_a22/}
}