@article{DAN_1984_277_1_a5,
     author = {A. V. Zhiber and A. B. Shabat},
     title = {Systems of equations $u_x=p(u,\,v)$, $v_y=q(u,\,v)$ that possess symmetries},
     journal = {Doklady Akademii Nauk},
     pages = {29--33},
     publisher = {mathdoc},
     volume = {277},
     number = {1},
     year = {1984},
     language = {ru},
     url = {http://geodesic.mathdoc.fr/item/DAN_1984_277_1_a5/}
}