@article{IM2_1996_60_2_a3,
     author = {V. V. Nikulin},
     title = {Reflection groups in {Lobachevskii} spaces and the denominator identity for {Lorentzian} {Kac--Moody} algebras},
     journal = {Izvestiya. Mathematics },
     pages = {305--334},
     publisher = {mathdoc},
     volume = {60},
     number = {2},
     year = {1996},
     language = {en},
     url = {http://geodesic.mathdoc.fr/item/IM2_1996_60_2_a3/}
}