@article{RM_2002_57_5_a1,
     author = {V. A. Gritsenko and V. V. Nikulin},
     title = {On classification of {Lorentzian} {Kac--Moody} algebras},
     journal = {Trudy Matematicheskogo Instituta imeni V.A. Steklova},
     pages = {921--979},
     publisher = {mathdoc},
     volume = {57},
     number = {5},
     year = {2002},
     language = {en},
     url = {http://geodesic.mathdoc.fr/item/RM_2002_57_5_a1/}
}