@article{IM_1980__61_142750,
     author = {Eduard Looijenga},
     title = {Invariant {Theory} for {Generalized} {Root} {Systems.}},
     journal = {Inventiones mathematicae},
     pages = {1--32},
     publisher = {mathdoc},
     volume = {61},
     year = {1980},
     zbl = {0436.17005},
     url = {http://geodesic.mathdoc.fr/item/IM_1980__61_142750/}
}