%0 Journal Article %A K. Urbanik %T A characterization of a class of convolutions %J Colloquium Mathematicum %D 1967 %P 239-249 %V 18 %N 1 %I mathdoc %U http://geodesic.mathdoc.fr/articles/10.4064/cm-18-1-239-249/ %R 10.4064/cm-18-1-239-249 %G en %F 10_4064_cm_18_1_239_249