@article{10_4153_CJM_1973_033_7,
     author = {Ringel, Claus Michael},
     title = {QF - 1 {Rings} of {Global} {Dimension} \ensuremath{\leqq} 2},
     journal = {Canadian journal of mathematics},
     pages = {345--352},
     year = {1973},
     volume = {25},
     number = {2},
     doi = {10.4153/CJM-1973-033-7},
     url = {http://geodesic.mathdoc.fr/articles/10.4153/CJM-1973-033-7/}
}