@article{ZNSL_1971_21_a1,
     author = {A. V. Ivanov},
     title = {On the structure of quasilinear second order elliptic equations},
     journal = {Zapiski Nauchnykh Seminarov POMI},
     pages = {5--33},
     publisher = {mathdoc},
     volume = {21},
     year = {1971},
     language = {ru},
     url = {http://geodesic.mathdoc.fr/item/ZNSL_1971_21_a1/}
}