@article{10_4171_dm_68,
     author = {Marc A. Rieffel},
     title = {Metrics on state spaces},
     journal = {Documenta mathematica},
     pages = {559--600},
     year = {1999},
     volume = {4},
     doi = {10.4171/dm/68},
     url = {http://geodesic.mathdoc.fr/articles/10.4171/dm/68/}
}