@article{DAN_1973_213_4_a12,
     author = {A. L. Fradkov and V. A. Yakubovich},
     title = {Necessary and sufficient conditions for absolute stability in classes of systems with two integral quadratic relations},
     journal = {Doklady Akademii Nauk},
     pages = {798--801},
     publisher = {mathdoc},
     volume = {213},
     number = {4},
     year = {1973},
     language = {ru},
     url = {http://geodesic.mathdoc.fr/item/DAN_1973_213_4_a12/}
}