@article{DE_1979_15_11_a16,
     author = {S. M. Shugrin},
     title = {Strong and weak extensions of differential {operators.~II}},
     journal = {Differencialʹnye uravneni\^a},
     pages = {2071--2084},
     publisher = {mathdoc},
     volume = {15},
     number = {11},
     year = {1979},
     language = {ru},
     url = {http://geodesic.mathdoc.fr/item/DE_1979_15_11_a16/}
}