1. On nonlinear contractions;Boyd;Proc. Amer. Math. Soc.,1968
2. Common fixed point theorems for multi-valued mappings;Chang;Math. Japon.,1995
3. Fixed points of generalized contractive multi-valued mappings;Daffer;J. Math. Anal. Appl.,1995
4. On a conjecture of S. Reich;Daffer;Proc. Amer. Math. Soc.,1996
5. Weakly contractive maps and elementary domain invariance theorem;Dugundji;Bull. Soc. Math. Gre. (N.S.),1978