@article{SF_1981__23_134527, author = {K.H. Hofmann and J.D. Lawson}, title = {The local theory of semigroups in nilpotent {Lie} groups.}, journal = {Semigroup forum}, pages = {343--358}, publisher = {mathdoc}, volume = {23}, year = {1981}, zbl = {0531.22002}, url = {http://geodesic.mathdoc.fr/item/SF_1981__23_134527/} }