@article{JOLT_2020_30_1_a9,
     author = {Herbert Abels and Ernest B. Vinberg},
     title = {Subsemigroups of {Nilpotent} {Lie} {Groups}},
     journal = {Journal of Lie Theory},
     pages = {171--178},
     year = {2020},
     volume = {30},
     number = {1},
     url = {http://geodesic.mathdoc.fr/item/JOLT_2020_30_1_a9/}
}