%0 Journal Article %A Shishkov, Ivailo %T $\Sigma$-products and selections of set-valued mappings %J Commentationes Mathematicae Universitatis Carolinae %D 2001 %P 203-207 %V 42 %N 1 %I mathdoc %U http://geodesic.mathdoc.fr/item/CMUC_2001__42_1_a15/ %G en %F CMUC_2001__42_1_a15