@article{02095722, title = {The free cover of a row contraction.}, journal = {Documenta Mathematica}, volume = {9}, year = {2004}, pages = {137-161}, zbl = {1049.46044}, language = {en}, url = {http://dml.mathdoc.fr/item/02095722} }
Arveson, William. The free cover of a row contraction.. Documenta Mathematica, Tome 9 (2004) pp. 137-161. http://gdmltest.u-ga.fr/item/02095722/