@article{JAC_2003__17_3_a6,
     author = {Takebayashi, Tadayoshi},
     title = {Poincar\'e series of the {Weyl} groups of the elliptic root systems $A_1^{(1,1)}$, $A_1^{(1,1)^*}$ and $A_2^{(1,1)}$.},
     journal = {Journal of Algebraic Combinatorics},
     pages = {211--223},
     publisher = {mathdoc},
     volume = {17},
     number = {3},
     year = {2003},
     language = {en},
     url = {http://geodesic.mathdoc.fr/item/JAC_2003__17_3_a6/}
}