@article{DAN_1961_139_1_a8,
     author = {M. Z. Solomyak},
     title = {Elliptic operators on two-dimensional manifolds},
     journal = {Doklady Akademii Nauk},
     pages = {37--39},
     publisher = {mathdoc},
     volume = {139},
     number = {1},
     year = {1961},
     language = {ru},
     url = {http://geodesic.mathdoc.fr/item/DAN_1961_139_1_a8/}
}