@article{GDZPPN002314134,
title = {Approximately Invariant Subspaces for Unbounded Linear Operators. II.},
journal = {Mathematische Annalen},
volume = {229},
year = {1977},
pages = {177-182},
zbl = {0345.47023},
url = {http://dml.mathdoc.fr/item/GDZPPN002314134}
}
Jorgensen, Palle E.T. Approximately Invariant Subspaces for Unbounded Linear Operators. II.. Mathematische Annalen, Tome 229 (1977) pp. 177-182. http://gdmltest.u-ga.fr/item/GDZPPN002314134/