@article{01701995,
title = {On the closure of the sum of closed subspaces.},
journal = {International Journal of Mathematics and Mathematical Sciences},
volume = {25},
year = {2001},
pages = {257-267},
doi = {10.1155/S0161171201005324},
zbl = {1007.46026},
language = {en},
url = {http://dml.mathdoc.fr/item/01701995}
}
Schochetman, Irwin E.; Smith, Robert L.; Tsui, Sze-Kai. On the closure of the sum of closed subspaces.. International Journal of Mathematics and Mathematical Sciences, Tome 25 (2001) pp. 257-267. doi : 10.1155/S0161171201005324. http://gdmltest.u-ga.fr/item/01701995/