Commutativity of intertwining operators for semisimple groups A. W. Knapp — 1982 Compositio Mathematica
Weyl group of a cuspidal parabolic A. W. Knapp — 1975 Annales scientifiques de l'École Normale Supérieure
A construction of unitary representations in parabolic rank two M. W. Baldoni-Silva; A. W. Knapp — 1989 Annali della Scuola Normale Superiore di Pisa - Classe di Scienze