@article{IM_1980__58_142722,
     author = {Claus Michael Ringel},
     title = {The {Rational} {Invariants} of the {Tame} {Quivers.}},
     journal = {Inventiones mathematicae},
     pages = {217--240},
     publisher = {mathdoc},
     volume = {58},
     year = {1980},
     zbl = {0433.15009},
     url = {http://geodesic.mathdoc.fr/item/IM_1980__58_142722/}
}