%0 Journal Article %A Tamás Keleti %T Difference functions of periodic measurable functions %J Fundamenta Mathematicae %D 1998 %P 15-32 %V 157 %N 1 %I mathdoc %U http://geodesic.mathdoc.fr/articles/10.4064/fm-157-1-15-32/ %R 10.4064/fm-157-1-15-32 %G en %F 10_4064_fm_157_1_15_32