@article{DAN_1969_187_1_a3,
     author = {R. Denchev},
     title = {The spectrum of singular integrals on regions with boundary},
     journal = {Doklady Akademii Nauk},
     pages = {18--20},
     publisher = {mathdoc},
     volume = {187},
     number = {1},
     year = {1969},
     language = {ru},
     url = {http://geodesic.mathdoc.fr/item/DAN_1969_187_1_a3/}
}