%0 Journal Article %A Šmarda, Bohumil %T Polarity compatible with a closure system %J Czechoslovak Mathematical Journal %D 1979 %P 13-20 %V 29 %N 1 %I mathdoc %U http://geodesic.mathdoc.fr/articles/10.21136/CMJ.1979.101574/ %R 10.21136/CMJ.1979.101574 %G en %F 10_21136_CMJ_1979_101574