%0 Journal Article %A Kuroki, Nobuaki %T On normal semigroups %J Czechoslovak Mathematical Journal %D 1977 %P 43-53 %V 27 %N 1 %I mathdoc %U http://geodesic.mathdoc.fr/articles/10.21136/CMJ.1977.101444/ %R 10.21136/CMJ.1977.101444 %G en %F 10_21136_CMJ_1977_101444