@article{DE_1976_12_7_a23,
     author = {T. I. Smagina},
     title = {Regularity classes for second order vectorial equations},
     journal = {Differencialʹnye uravneni\^a},
     pages = {1320--1322},
     publisher = {mathdoc},
     volume = {12},
     number = {7},
     year = {1976},
     language = {ru},
     url = {http://geodesic.mathdoc.fr/item/DE_1976_12_7_a23/}
}