@article{GDZPPN002212226,
title = {Lusin's condition (N) and mappings of the class W1, n.},
journal = {Journal f\"ur die reine und angewandte Mathematik},
volume = {468},
year = {1995},
pages = {19-36},
zbl = {0812.30007},
url = {http://dml.mathdoc.fr/item/GDZPPN002212226}
}
Martio, Olli; Maly, Jan. Lusin's condition (N) and mappings of the class W1, n.. Journal für die reine und angewandte Mathematik, Tome 468 (1995) pp. 19-36. http://gdmltest.u-ga.fr/item/GDZPPN002212226/