@article{MOMA_1991__112_3_178547,
     author = {Karl-Hermann Neeb},
     title = {Objects {Dual} to {Subsemigroups} of {Groups.}},
     journal = {Monatshefte f\"ur Mathematik},
     pages = {303--322},
     publisher = {mathdoc},
     volume = {112},
     number = {3},
     year = {1991},
     zbl = {0737.22002},
     url = {http://geodesic.mathdoc.fr/item/MOMA_1991__112_3_178547/}
}