@article{GDZPPN002436116, title = {Towards a "Matrix Theory" for Unbounded Operator Matrices.}, journal = {Mathematische Zeitschrift}, volume = {202}, year = {1989}, pages = {57-68}, zbl = {0672.47001}, url = {http://dml.mathdoc.fr/item/GDZPPN002436116} }
Nagel, Rainer. Towards a "Matrix Theory" for Unbounded Operator Matrices.. Mathematische Zeitschrift, Tome 202 (1989) pp. 57-68. http://gdmltest.u-ga.fr/item/GDZPPN002436116/