Operator orderings and Meixner-Pollaczek polynomials
  The aim of this paper is to give identities which are generalizations of the formulas given by Koornwinder [J. Math. Phys. 30, (1989)] and Hamdi-Zeng [J. Math. Phys. 51, (2010)]. Our proofs are much simpler than and different from the previous investigations. 
Genki Shibukawa
math-ph math.CA math.MP