@article{IM_1994__116_1-3_144191,
     author = {Peter Littelmann},
     title = {A {Littlewood-Richardson} rule for symmetrizable {Kac-Moody} algebras.},
     journal = {Inventiones mathematicae},
     pages = {329--346},
     publisher = {mathdoc},
     volume = {116},
     number = {1-3},
     year = {1994},
     zbl = {0805.17019},
     url = {http://geodesic.mathdoc.fr/item/IM_1994__116_1-3_144191/}
}