1. Coincidence point theorems and minimization theorems in metric spaces;Chang;Fuzzy Sets Syst.,1997
2. Note on the results with lower semi-continuity;Chen;Bull. Korean Math. Soc.,2002
3. Equivalents of an approximate variational principle for vector-valued functions and applications;Chen;Math. Methods Oper. Res.,1999
4. Vector Optimization, Set-Valued and Variational Analysis;Chen,2005
5. Gradual elements in a fuzzy set;Dubois;Soft Comput.,2008