1. Chaps. I–III;Bourbaki,1970
2. Nilpotent orbits, normality, and Hamiltonian group actions;Brylinski;J. Amer. Math. Soc.,1994
3. The restriction of admissible representations to n;Casselman;Math. Ann.,1978
4. Enveloping Algebras;Dixmier,1977
5. Commutative Algebra with a View toward Algebraic Geometry;Eisenbud,1994