@article{01596864,
title = {Maximal semigroups in the divisible hull of lattices in nilpotent Lie groups.},
journal = {Journal of Lie Theory},
volume = {11},
year = {2001},
pages = {1-8},
zbl = {0967.22005},
language = {en},
url = {http://dml.mathdoc.fr/item/01596864}
}
do Rocio, Osvaldo Germano. Maximal semigroups in the divisible hull of lattices in nilpotent Lie groups.. Journal of Lie Theory, Tome 11 (2001) pp. 1-8. http://gdmltest.u-ga.fr/item/01596864/