%0 Journal Article %A Jacek Fabrykowski %T Squares in difference sets %J Acta Arithmetica %D 1992 %P 199-208 %V 61 %N 2 %I mathdoc %U http://geodesic.mathdoc.fr/articles/10.4064/aa-61-2-199-208/ %R 10.4064/aa-61-2-199-208 %G en %F 10_4064_aa_61_2_199_208