@article{10_4153_CJM_1976_066_4,
     author = {Magid, Andy R.},
     title = {Fundamental, {Picard,} and {Class} {Groups} of {Rings} of {Invariants}},
     journal = {Canadian journal of mathematics},
     pages = {659--664},
     year = {1976},
     volume = {28},
     number = {3},
     doi = {10.4153/CJM-1976-066-4},
     url = {http://geodesic.mathdoc.fr/articles/10.4153/CJM-1976-066-4/}
}