13 pages, 2 figures.-- MSC2000 codes: 33C45, 82B10, 42C05, 81Q05.-- Contributed to: International Workshop on Orthogonal Polynomials in Mathematical Physics (IWOP'96, in honour of Professor André Ronveaux, Leganés, Spain, June 24-26, 1996).
MR#: MR1466766 (98i:33009)
Zbl#: Zbl 0951.33009