%0 Journal Article %A Davvaz, B. %T Characterizations of sub-semihypergroups by various triangular norms %J Czechoslovak Mathematical Journal %D 2005 %P 923-932 %V 55 %N 4 %U http://geodesic.mathdoc.fr/item/CMJ_2005_55_4_a8/ %G en %F CMJ_2005_55_4_a8