@article{RM_1999_54_3_a9,
     author = {D. V. Lagno},
     title = {A~characterization of the imaginary roots of hyperbolic {Kac--Moody} algebras},
     journal = {Trudy Matematicheskogo Instituta imeni V.A. Steklova},
     pages = {636--637},
     publisher = {mathdoc},
     volume = {54},
     number = {3},
     year = {1999},
     language = {en},
     url = {http://geodesic.mathdoc.fr/item/RM_1999_54_3_a9/}
}