1. Generators and Relations for Discrete Groups;Coxeter,1965
2. Lie Algebras;Jacobson,1962
3. Lie algebras associated with generalized Cartan matrices;Moody;Bull. Am. Math. Soc.,1967
4. Algebres de Lie Semi-Simple Complexes;Serre,1966
5. Verma, D.-N. (private communication).