@article{SF_1972__5_133928,
     author = {A.B. Engel},
     title = {The homomorphic image of a {T} -semigroup.},
     journal = {Semigroup forum},
     pages = {120--126},
     publisher = {mathdoc},
     volume = {5},
     year = {1972},
     zbl = {0259.20061},
     url = {http://geodesic.mathdoc.fr/item/SF_1972__5_133928/}
}