@article{MAN_1988__282_2_164460,
     author = {Torben Maack Bisgaard},
     title = {Extension of {Characters} on {*-Semigroups.}},
     journal = {Mathematische Annalen},
     pages = {251--258},
     publisher = {mathdoc},
     volume = {282},
     number = {2},
     year = {1988},
     zbl = {0629.20040},
     url = {http://geodesic.mathdoc.fr/item/MAN_1988__282_2_164460/}
}