@article{AM2_1979__19_136819,
     author = {Kenneth D. Jr. Magill},
     title = {Green's {L-relation} for semigroups and compactifications.},
     journal = {Aequationes mathematicae},
     pages = {123--133},
     publisher = {mathdoc},
     volume = {19},
     year = {1979},
     zbl = {0442.20051},
     url = {http://geodesic.mathdoc.fr/item/AM2_1979__19_136819/}
}