Dimension of spaces of automorphic forms
This first appeared in the Proceedings of the AMS Symposium at Boulder, Colorado, held in the summer of 1965.
The classification of representations of real reductive groups
This was written in 1973. It first appeared as a preprint distributed by the Institute for Advanced Study, and was later (1988) published by the A.M.S. in Math. Surveys and Monographs 31.
Notes on Knapp-Zuckerman theory
This has not been published before. It was written around 1977, just after A. Knapp and G. Zuckerman had announced their results on reducible unitary principal series, subsequently explained in a talk at the A.M.S. 1977 summer school in Corvallis (pp. 93-105 of the published proceedings of that conference.)
On unitary representations of the Virasoro algebra
First appeared in Infinite-dimensional Lie algebras and their applications, World Scientific, 1988.
The factorization of a polynomial defined by partitions
First appeared in Commun. Math. Phys. 124 (1989).