%0 Journal Article %A Arhangel'skii, A. V. %A HuĊĦek, M. %T Extensions of topological and semitopological groups and the product operation %J Commentationes Mathematicae Universitatis Carolinae %D 2001 %P 173-186 %V 42 %N 1 %I mathdoc %U http://geodesic.mathdoc.fr/item/CMUC_2001__42_1_a12/ %G en %F CMUC_2001__42_1_a12