%0 Journal Article
%A James Lepowsky
%A Robert V. Moody
%T Hyperbolic Lie Algebras and Quasi-Regular Cusps on Hilbert  Modular Surfaces.
%J Mathematische Annalen
%D 1979
%P 63-88
%V 245
%I mathdoc
%U http://geodesic.mathdoc.fr/item/MAN_1979__245_163311/
%F MAN_1979__245_163311