@article{DAN_1992_322_4_a5,
     author = {Ya. Z. Tsypkin},
     title = {Circular criteria for robust stability of nonlinear discrete},
     journal = {Doklady Akademii Nauk},
     pages = {656--661},
     publisher = {mathdoc},
     volume = {322},
     number = {4},
     year = {1992},
     language = {ru},
     url = {http://geodesic.mathdoc.fr/item/DAN_1992_322_4_a5/}
}