@article{SF_1992__44_1_135135,
     author = {H. Umoh},
     title = {a-inflatable semigroups.},
     journal = {Semigroup forum},
     pages = {118--124},
     year = {1992},
     volume = {44},
     number = {1},
     zbl = {0759.22008},
     url = {http://geodesic.mathdoc.fr/item/SF_1992__44_1_135135/}
}