1. Ya.I. Alber, S. Guerre-Delabrière and L. Zelenko, The principle of weakly contractive mappings in metric spaces, Comm. Appl. Nonlinear Analysis 5 (1) (1998), 45–68.
2. E. Asplund, Fréchet differentiability of convex functions, Acta. Math. 121 (1968), 31–47.
3. J.M. Ayerbe Toledano, T. Dominguez Benavides and G. López Acedo, Measures of Noncompactness in Metric Fixed Point theory, Birkhauser, Basel, 1997.
4. J.M. Ball and N.S. Nadirashvili, Universal singular sets for one-dimensional variational problems, Calc. Var. 1 (1993), 429–438.
5. H.H. Bauschke, A norm convergence result on random products of relaxed projections in Hilbert space, Trans. Amer. Math. Soc. 347 (1995), 1365–1373.