%0 Journal Article %A Duncan, Richard %T On 2-Summing Operators %J Canadian mathematical bulletin %D 1974 %P 493-498 %V 17 %N 4 %U http://geodesic.mathdoc.fr/articles/10.4153/CMB-1974-087-5/ %R 10.4153/CMB-1974-087-5 %F 10_4153_CMB_1974_087_5