@article{MM_1990_2_9_a12,
     author = {M. M. Lavrent'ev (Jn.)},
     title = {A~priori smoothness of solutions for number of equations of a~changing type},
     journal = {Matemati\v{c}eskoe modelirovanie},
     pages = {145--153},
     publisher = {mathdoc},
     volume = {2},
     number = {9},
     year = {1990},
     language = {ru},
     url = {http://geodesic.mathdoc.fr/item/MM_1990_2_9_a12/}
}