@article{10_4171_dm_162,
     author = {William Arveson},
     title = {The free cover of a row contraction},
     journal = {Documenta mathematica},
     pages = {137--161},
     year = {2004},
     volume = {9},
     doi = {10.4171/dm/162},
     url = {http://geodesic.mathdoc.fr/articles/10.4171/dm/162/}
}