@article{SF_1971__2_133810,
     author = {K. Keimel},
     title = {Baer extensions of rings and {Stone} extensions of semigroups.},
     journal = {Semigroup forum},
     pages = {55--63},
     publisher = {mathdoc},
     volume = {2},
     year = {1971},
     zbl = {0225.20041},
     url = {http://geodesic.mathdoc.fr/item/SF_1971__2_133810/}
}