@article{RM_1969_24_3_a15,
     author = {E. V. Radkevich},
     title = {The smoothness of solutions of the first boundary value problem for second order differential equations with a~non-negative characteristic form},
     journal = {Trudy Matematicheskogo Instituta imeni V.A. Steklova},
     publisher = {mathdoc},
     volume = {24},
     number = {3},
     year = {1969},
     language = {ru},
     url = {http://geodesic.mathdoc.fr/item/RM_1969_24_3_a15/}
}