If you have trouble locating any of these papers please contact an author for a reprint. A few of the later G.P. Srivastava Group papers are available as on line Postscript documents.
T P Humphreys and G P Srivastava
Phys Stat Sol (b) 112, 581 (1982).
T P Humphreys, G P Srivastava and R H Williams
J Phys C 19, 1259-1271 (1986).