@article{FAA_1984_18_2_a19,
     author = {P. A. Frolov},
     title = {Topological structure of elliptic boundary problems in space},
     journal = {Funkcionalʹnyj analiz i ego prilo\v{z}eni\^a},
     pages = {81--82},
     publisher = {mathdoc},
     volume = {18},
     number = {2},
     year = {1984},
     language = {ru},
     url = {http://geodesic.mathdoc.fr/item/FAA_1984_18_2_a19/}
}