@article{DAN_1962_146_4_a10,
     author = {N. N. Ural'tseva},
     title = {General second-order quasi-linear equations and certain classes of systems of equations of elliptic type},
     journal = {Doklady Akademii Nauk},
     pages = {778--781},
     publisher = {mathdoc},
     volume = {146},
     number = {4},
     year = {1962},
     language = {ru},
     url = {http://geodesic.mathdoc.fr/item/DAN_1962_146_4_a10/}
}