1. Characterization theorems for orthogonal polynomials;Al-Salam,1990
2. Orthogonal Polynomials of Several Variables;Dunkl,2001
3. Discrete models of the harmonic oscillator and a discrete analogue of Gauss' hypergeometric equation;Grünbaum;Ramanujan J.,2001
4. Linear growth models with many types and multidimensional Hahn polynomials;Karlin,1975
5. A multi-dimensional linear growth birth and death process;Milch;Ann. Math. Statist.,1968