Appeard in Contemporary Mathematics 143 (1993) (special volume in memory of Emil Grosswald, edited by Marvin Knopp and Mark Sheingorn),579-608.
It was Herb Wilf's brilliant insight that turned a mere algorithm (the so-called Zeilberger algorithm, a.k.a. as the Gosper-Zeilberger algorithm) into a full-fledged theory (WZ theory). This article is just a modest beginning to realizing its full potential. Even though, it has already found quite a few applications to series acceleration and it was exactly what was needed to conclude the Ahlgren- Ono proof of Beukers's conjecture.
Doron Zeilberger's List of Papers