@article{01026385,
title = {On the spectral set of a solvable Lie algebra of operators.},
journal = {Portugaliae Mathematica. Nova S\'erie},
volume = {54},
year = {1997},
pages = {85-94},
zbl = {0891.47005},
language = {en},
url = {http://dml.mathdoc.fr/item/01026385}
}
Boasso, Enrico. On the spectral set of a solvable Lie algebra of operators.. Portugaliae Mathematica. Nova Série, Tome 54 (1997) pp. 85-94. http://gdmltest.u-ga.fr/item/01026385/