@article{SF_1975__10_134098,
     author = {M. Friedberg},
     title = {On compactifying semigroups.},
     journal = {Semigroup forum},
     pages = {39--54},
     publisher = {mathdoc},
     volume = {10},
     year = {1975},
     zbl = {0297.22002},
     url = {http://geodesic.mathdoc.fr/item/SF_1975__10_134098/}
}