%0 Journal Article %A Steven G. Krantz %T Estimates for Integral Kernelsof mixed Type, Fractional Integration Operators, and Optimal Estimates for the ... Operator. %J Manuscripta mathematica %D 1979 %P 21-52 %V 30 %I mathdoc %U http://geodesic.mathdoc.fr/item/MM2_1979__30_154672/ %F MM2_1979__30_154672