@article{10_4153_CJM_1998_015_5,
     author = {Davidson, Kenneth R. and Popescu, Gelu},
     title = {Noncommutative {Disc} {Algebras} for {Semigroups}},
     journal = {Canadian journal of mathematics},
     pages = {290--311},
     year = {1998},
     volume = {50},
     number = {2},
     doi = {10.4153/CJM-1998-015-5},
     url = {http://geodesic.mathdoc.fr/articles/10.4153/CJM-1998-015-5/}
}