Algorithm and Complexity:

On Steiner Minimal Trees with Lp Distances, Zicheng Liu, Ding-Zhu Du, Algorithmica (1992) 7.

Minimum Steiner Trees in Normed Planes, Ding-Zhu Du, Biao Gao, Ronald L. Graham, Zicheng Liu, Peng-Jun Wang, Discrete and Computational Geometry 9 (1993).

Efficient Average-Case Algorithms for the Modular Group, Jin-Yi Cai, Wolfgang Fuchs, Dexter Kozen, Zicheng Liu, Proceedings of 35th Symposium on Foundations of Computer Science (FOCS 1994).

The Bounded Membership Problem of the Monoid SL2(N), Jin-Yi Cai, Zicheng Liu, Mathematical and Systems Theory, Vol 29,1996, 573-587.