@article{JLT_1991_1_2_a9,
     author = {K. H. Hofmann and W. Ruppert},
     title = {Divisible {Subsemigroups} of {Lie} {Groups}},
     journal = {Journal of Lie theory},
     pages = {205--216},
     publisher = {mathdoc},
     volume = {1},
     number = {2},
     year = {1991},
     url = {http://geodesic.mathdoc.fr/item/JLT_1991_1_2_a9/}
}