@article{BAG_1991__31_138478,
     author = {I. Jagnow},
     title = {Erweiterungen linearer involutorischer {Halbgruppen}},
     journal = {Beitr\"age zur Algebra und Geometrie},
     pages = {103--120},
     publisher = {mathdoc},
     volume = {31},
     year = {1991},
     language = {de},
     url = {http://geodesic.mathdoc.fr/item/BAG_1991__31_138478/}
}