%0 Journal Article %A Arno van den Essen %T A counterexample to a conjecture of Drużkowski and Rusek %J Annales Polonici Mathematici %D 1995 %P 173-176 %V 62 %N 2 %I mathdoc %U http://geodesic.mathdoc.fr/articles/10.4064/ap-62-2-173-176/ %R 10.4064/ap-62-2-173-176 %G pl %F 10_4064_ap_62_2_173_176