%0 Journal Article %A Pták, Vlastimil %T Openness of linear mappings in $LF$-spaces %J Czechoslovak Mathematical Journal %D 1969 %P 547-552 %V 19 %N 3 %I mathdoc %U http://geodesic.mathdoc.fr/articles/10.21136/CMJ.1969.100921/ %R 10.21136/CMJ.1969.100921 %G en %F 10_21136_CMJ_1969_100921