@article{GDZPPN002434032, title = {On the Closedness of the Sum of Two Closed Operators.}, journal = {Mathematische Zeitschrift}, volume = {194}, year = {1987}, pages = {189-202}, zbl = {0615.47002}, url = {http://dml.mathdoc.fr/item/GDZPPN002434032} }
Dore, Giovanni; Venni, Alberto. On the Closedness of the Sum of Two Closed Operators.. Mathematische Zeitschrift, Tome 194 (1987) pp. 189-202. http://gdmltest.u-ga.fr/item/GDZPPN002434032/