1. Ortogonalidad en Espacios Normados;Alonso,1984
2. Chebyshev centers in normed spaces;Amir;J. Approx. Theory,1984
3. Characterizations of Inner Product Spaces;Amir,1986
4. The Hausdorff metric and Chebyshev centers;Borwein;J. Approx. Theory,1980
5. Orthogonality in normed linear spaces;Carlsson;Ark. Mat.,1961