@article{DE_1974_10_2_a13,
     author = {Yu. A. Brychkov},
     title = {Smoothness with respect to part of the variables for solutions of linear partial differential equations},
     journal = {Differencialʹnye uravneni\^a},
     pages = {281--289},
     publisher = {mathdoc},
     volume = {10},
     number = {2},
     year = {1974},
     language = {ru},
     url = {http://geodesic.mathdoc.fr/item/DE_1974_10_2_a13/}
}