@article{SF_1987__36_134893,
     author = {F. Catino},
     title = {Factorizable semigroups.},
     journal = {Semigroup forum},
     pages = {167--174},
     year = {1987},
     volume = {36},
     zbl = {0619.20044},
     url = {http://geodesic.mathdoc.fr/item/SF_1987__36_134893/}
}