@article{IM2_1996_60_6_a1,
     author = {A. S. Belov and S. V. Konyagin},
     title = {An estimate of the free term of a~non-negative trigonometric polynomial with integer coefficients},
     journal = {Izvestiya. Mathematics},
     pages = {1123--1182},
     year = {1996},
     volume = {60},
     number = {6},
     language = {en},
     url = {http://geodesic.mathdoc.fr/item/IM2_1996_60_6_a1/}
}