%0 Journal Article
%A F. B. Koval'chik
%T Certain analogues of the Hardy--Litlewood problem and density methods
%J Zapiski Nauchnykh Seminarov POMI
%D 1981
%P 121-142
%V 112
%I mathdoc
%U http://geodesic.mathdoc.fr/item/ZNSL_1981_112_a9/
%G ru
%F ZNSL_1981_112_a9