@article{DAN_1971_198_6_a2,
     author = {L. A. Kogan},
     title = {Vinogradov{\textquoteright}s conjecture on the least quadratic nonresidue and representation of numbers by quadratic forms},
     journal = {Doklady Akademii Nauk},
     pages = {1263--1264},
     publisher = {mathdoc},
     volume = {198},
     number = {6},
     year = {1971},
     language = {ru},
     url = {http://geodesic.mathdoc.fr/item/DAN_1971_198_6_a2/}
}