@article{10_4153_CJM_1972_044_5,
     author = {Choi, Man-Duen},
     title = {Positive {Linear} {Maps} on {C*-Algebras}},
     journal = {Canadian journal of mathematics},
     pages = {520--529},
     year = {1972},
     volume = {24},
     number = {3},
     doi = {10.4153/CJM-1972-044-5},
     url = {http://geodesic.mathdoc.fr/articles/10.4153/CJM-1972-044-5/}
}