%0 Journal Article %A Mieczysław K. Mentzen %T Ergodic properties of group extensions of dynamical systems with discrete spectra %J Studia Mathematica %D 1991 %P 19-31 %V 101 %N 1 %I mathdoc %U http://geodesic.mathdoc.fr/articles/10.4064/sm-101-1-19-31/ %R 10.4064/sm-101-1-19-31 %G en %F 10_4064_sm_101_1_19_31