%0 Journal Article %A Ernest Płonka %T Idempotent words in nilpotent groups %J Colloquium Mathematicum %D 1974 %P 83-85 %V 29 %N 1 %I mathdoc %U http://geodesic.mathdoc.fr/articles/10.4064/cm-29-1-83-85/ %R 10.4064/cm-29-1-83-85 %G en %F 10_4064_cm_29_1_83_85