@article{DE_2004_40_11_a3,
     author = {N. N. Butenina and N. S. Starodubrovskaya},
     title = {A stable fixed focus and its immunity zone in a second-order controlled dynamical system},
     journal = {Differencialʹnye uravneni\^a},
     pages = {1468--1478},
     publisher = {mathdoc},
     volume = {40},
     number = {11},
     year = {2004},
     language = {ru},
     url = {http://geodesic.mathdoc.fr/item/DE_2004_40_11_a3/}
}