1. A.G. Aksoy, M.S. Borman, A.L. Westfall, Compactness and measures of noncompactness in metric trees, in Banach and Function Spaces II (Yokohama Publ., Yokohama, 2008), pp. 277–292
2. A.G. Aksoy, M.A. Khamsi, Fixed points of uniformly lipschitzian mappings in metric trees. Sci. Math. Jpn. 65(1), 31–41 (2007)
3. A.G. Aksoy, B. Maurizi, Metric trees, hyperconvex hulls and extensions. Turkish J. Math. 32(2), 219–234 (2008)
4. N. Aronszajn, P. Panitchpakdi, Extension of uniformly continuous transformations and hyperconvex metric spaces. Pacific J. Math. 6, 405–439 (1956)
5. J.B. Baillon, Nonexpansive mapping and hyperconvex spaces, in Fixed Point Theory and Its Applications (Berkeley, CA, 1986). Contemporary Mathematics, vol. 72 (American Mathematical Society, Providence, 1988), pp. 11–19