@article{MAN_1994__300_2_165256,
     author = {Claus Michael Ringel},
     title = {The spectral radius of the {Coxeter} transformations for a generalized {Cartan} matrix.},
     journal = {Mathematische Annalen},
     pages = {331--340},
     publisher = {mathdoc},
     volume = {300},
     number = {2},
     year = {1994},
     zbl = {0819.15008},
     url = {http://geodesic.mathdoc.fr/item/MAN_1994__300_2_165256/}
}