%0 Journal Article %A K.D. jr. Magill %A P.R. Misra %T Principal continuum congruences, regular ...-classes and local subsemigroups. %J Semigroup forum %D 1990 %P 205-226 %V 40 %N 1 %I mathdoc %U http://geodesic.mathdoc.fr/item/SF_1990__40_1_135020/ %F SF_1990__40_1_135020