On Systems of Finite Sets with Constraints on Their Unions and Intersections. - Da-Lun Wang (J. Comb. Theory A, 1977)

Some results about the Chvátal conjecture. - Da-Lun Wang; Ping Wang (Discret. Math., 1978)

Depth-First Search as a Combinatorial Correspondence. - Ira M. Gessel; Da-Lun Wang (J. Comb. Theory A, 1979)