%0 Journal Article %A J. Kopeć %T Some criterions of Nӧrlund summability %J Commentationes Mathematicae %D 1969 %P 67-75 %V 13 %N 1 %I mathdoc %U http://geodesic.mathdoc.fr/articles/10.14708/cm.v13i1.5658/ %R 10.14708/cm.v13i1.5658 %G pl %F 10_14708_cm_v13i1_5658