Dwork's conjecture on unit root zeta functions. Wan, Daqing — 1999 Annals of Mathematics. Second Series
Hilbert sets and zeta functions over finite fields. Daqing Wan — 1992 Journal für die reine und angewandte Mathematik
Permutation Polynomials of the Form x... f (x...) and Their Group Structure. Rudolf Lidl; Daqing Wan — 1991 Monatshefte für Mathematik