Appeared in Invent. Math. 108 (1992), 575-633.
This is a WZ classic.
.pdf version of preprint
.pdf version of reprint
Added Nov. 8. , 2011: Shaoshi Chen, Christoph Koutschan, and Garth Payne have recently solved the 20-year conjecture made in this paper. As soon as their paper is posted, I will put a link to it. Meanwhile watch Shaoshi Chen's fascinating lecture: part 1, part 2.
Added July 18, 2015: The long-awaited paper Proof of the Wilf-Zeilberger Conjecture by Shaoshi Chen and Christoph Koutschan is now available!
Added Feb. 13, 2017: Bryan Ek pointed out that the factor in front of F(n,k) on the right of p. 624, line 12, q^(n-k) should be q^(n-k+1) and (q^k-q^k) should be (q^k - q^b)
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