%0 Journal Article %T Journal for the Cultivation of Mathematics. Abstracts %J Czechoslovak Mathematical Journal %D 1957 %P 320-322 %V 07 %N 2 %I mathdoc %U http://geodesic.mathdoc.fr/articles/10.21136/CMJ.1957.100252/ %R 10.21136/CMJ.1957.100252 %G en %F 10_21136_CMJ_1957_100252