%0 Journal Article %A Ryszard Grząślewicz %T Extreme operators on 2-dimensional $l_p$-spaces %J Colloquium Mathematicum %D 1981 %P 309-315 %V 44 %N 2 %I mathdoc %U http://geodesic.mathdoc.fr/articles/10.4064/cm-44-2-309-315/ %R 10.4064/cm-44-2-309-315 %G en %F 10_4064_cm_44_2_309_315