[1] A. Bayati Eshkaftaki, D-Norm and isometries on $c_{0}$ spaces, Oper. Matrices, 41 (2017), 1141-1148.
[2] G. Birkhoff, Orthogonality in linear metric spaces, Duke Math. J., 1(2) (1935), 169-172,
[3] C. Sánchez, Diameter preserving linear maps and isometries, Arch. Math., 73 (1999), 373-379.
[4] G.M. Church, Extreme Points in Banach Spaces, Oklahoma State University, 1974.
[5] J. Hagler, Counterexample to several questions about Banach spaces, Stud. Math., 3 (1977), 289-308.