@article{DAN_1968_181_6_a13,
     author = {P. A. Frolov},
     title = {Connected components of real elliptic systems on the plane},
     journal = {Doklady Akademii Nauk},
     pages = {1350--1353},
     publisher = {mathdoc},
     volume = {181},
     number = {6},
     year = {1968},
     language = {ru},
     url = {http://geodesic.mathdoc.fr/item/DAN_1968_181_6_a13/}
}