%0 Journal Article %A M. Libine %T The Two-Loop Ladder Diagram and Representations of U(2,2) %J Journal of Lie theory %D 2017 %P 771-8 %V 27 %N 3 %U http://geodesic.mathdoc.fr/item/JLT_2017_27_3_JLT_2017_27_3_a7/ %F JLT_2017_27_3_JLT_2017_27_3_a7