@article{TM_2018_303_a18,
     author = {I. D. Shkredov and I. E. Shparlinski},
     title = {Double character sums with intervals and arbitrary sets},
     journal = {Trudy Matematicheskogo Instituta imeni V.A. Steklova},
     pages = {258--278},
     publisher = {mathdoc},
     volume = {303},
     year = {2018},
     language = {ru},
     url = {http://geodesic.mathdoc.fr/item/TM_2018_303_a18/}
}