1. Norm Derivatives and Characterizations of Inner Product Spaces;Alsina,2010
2. Orthogonality in linear metric spaces;Birkhoff;Duke Math. J.,1935
3. Ball-covering property of Banach spaces;Cheng;Isr. J. Math.,2006
4. Minimal ball-coverings in Banach spaces and their application;Cheng;Stud. Math.,2009
5. A note on ball-covering property of Banach spaces;Cheng;J. Math. Anal. Appl.,2010