@article{IM2_1997_61_4_a7,
     author = {V. A. Skvortsov},
     title = {Approximate symmetric variation and the {Lusin} $N$-property},
     journal = {Izvestiya. Mathematics },
     pages = {831--841},
     publisher = {mathdoc},
     volume = {61},
     number = {4},
     year = {1997},
     language = {en},
     url = {http://geodesic.mathdoc.fr/item/IM2_1997_61_4_a7/}
}