@article{SM_1970_12_4_a5,
     author = {E. Ya. Khruslov},
     title = {On~the {Neumann} boundary problem in a~domain with complicated boundary},
     journal = {Sbornik. Mathematics},
     pages = {553--571},
     publisher = {mathdoc},
     volume = {12},
     number = {4},
     year = {1970},
     language = {en},
     url = {http://geodesic.mathdoc.fr/item/SM_1970_12_4_a5/}
}