@article{IM2_1968_2_6_a7, author = {M. I. Freidlin}, title = {On the smoothness of solutions of degenerate elliptic equations}, journal = {Izvestiya. Mathematics }, pages = {1337--1359}, publisher = {mathdoc}, volume = {2}, number = {6}, year = {1968}, language = {en}, url = {http://geodesic.mathdoc.fr/item/IM2_1968_2_6_a7/} }