@article{SF_1974__9_134079,
     author = {B.M. Schein and L.M. Gluskin},
     title = {Ideal extensions of  irreductive semigroups.},
     journal = {Semigroup forum},
     pages = {216--240},
     year = {1974},
     volume = {9},
     zbl = {0293.20050},
     url = {http://geodesic.mathdoc.fr/item/SF_1974__9_134079/}
}