@article{SM_1995_81_1_a6,
     author = {A. K. Gushchin and V. P. Mikhailov},
     title = {On solvability of nonlocal problems for a~second-order elliptic equation},
     journal = {Sbornik. Mathematics},
     pages = {101--136},
     year = {1995},
     volume = {81},
     number = {1},
     language = {en},
     url = {http://geodesic.mathdoc.fr/item/SM_1995_81_1_a6/}
}