@article{10_4064__26_1_433_447,
     author = {Claus Michael Ringel},
     title = {Hall algebras},
     journal = {Banach Center Publications},
     pages = {433--447},
     year = {1990},
     volume = {26},
     number = {1},
     doi = {10.4064/-26-1-433-447},
     language = {de},
     url = {http://geodesic.mathdoc.fr/articles/10.4064/-26-1-433-447/}
}