@article{DAN_1974_219_1_a5,
     author = {F. B. Koval'chik},
     title = {Density theorems and the distribution of primes in sectors and progressions},
     journal = {Doklady Akademii Nauk},
     pages = {31--34},
     publisher = {mathdoc},
     volume = {219},
     number = {1},
     year = {1974},
     language = {ru},
     url = {http://geodesic.mathdoc.fr/item/DAN_1974_219_1_a5/}
}