@article{TM_1994_207_a4,
     author = {S. V. Bochkarev},
     title = {Estimates of some character sums},
     journal = {Trudy Matematicheskogo Instituta imeni V.A. Steklova},
     pages = {42--53},
     year = {1994},
     volume = {207},
     language = {ru},
     url = {http://geodesic.mathdoc.fr/item/TM_1994_207_a4/}
}