@article{ZNSL_1974_47_a12,
     author = {E. M. Il'in},
     title = {Singularities of weak solutions of elliptic equations with discontinuous coefficients. {II.~Angular} points of lines of gap},
     journal = {Zapiski Nauchnykh Seminarov POMI},
     pages = {166--169},
     year = {1974},
     volume = {47},
     language = {ru},
     url = {http://geodesic.mathdoc.fr/item/ZNSL_1974_47_a12/}
}