@article{DAN_1971_199_1_a7,
     author = {V. V. Strygin},
     title = {``Exchange of stabilities'' and bifurcation of small auto-oscillations of systems of differential equations with 
},
     journal = {Doklady Akademii Nauk},
     pages = {33--35},
     publisher = {mathdoc},
     volume = {199},
     number = {1},
     year = {1971},
     language = {ru},
     url = {http://geodesic.mathdoc.fr/item/DAN_1971_199_1_a7/}
}