Three-element codes with one d-primitive word. - Zheng-Zhu Li; Y. S. Tsai (Acta Informatica, 2004)

Classifications of Dense Languages. - Zheng-Zhu Li; Huei-Jan Shyr; Y. S. Tsai (Acta Informatica, 2006)

Overlapping words, codes, disjunctivity and density of languages. - Kuo-Hsiang Chen; Zheng-Zhu Li; Yen-Shung Tsai (Int. J. Comput. Math., 2008)

Automata Accepting Bifix Codes. - Zheng-Zhu Li; Huei-Jan Shyr; Yen-Shung Tsai (J. Autom. Lang. Comb., 2008)

Classifications of bifix codes. - Zheng-Zhu Li; Y. S. Tsai (Int. J. Comput. Math., 2010)

Some properties of the disjunctive languages contained in Q. - Zheng-Zhu Li; Y. S. Tsai (Acta Informatica, 2011)