@article{TM_1997_219_a20,
     author = {S. B. Stechkin},
     title = {Turan's {Problem} for {Trigonometric} {Sums}},
     journal = {Trudy Matematicheskogo Instituta imeni V.A. Steklova},
     pages = {335--339},
     publisher = {mathdoc},
     volume = {219},
     year = {1997},
     language = {ru},
     url = {http://geodesic.mathdoc.fr/item/TM_1997_219_a20/}
}