@article{GDZPPN002207923,
title = {Boundaries for left-invariant sub-elliptic operators on semidirect products of nilpotent and abelian groups.},
journal = {Journal f\"ur die reine und angewandte Mathematik},
volume = {405},
year = {1990},
pages = {1-38},
zbl = {0699.22012},
url = {http://dml.mathdoc.fr/item/GDZPPN002207923}
}
Hulanicki, A.; Damek, Eva. Boundaries for left-invariant sub-elliptic operators on semidirect products of nilpotent and abelian groups.. Journal für die reine und angewandte Mathematik, Tome 405 (1990) pp. 1-38. http://gdmltest.u-ga.fr/item/GDZPPN002207923/