%0 Journal Article
%A Xiaoyi Tian
%A Qingxiang Xu
%T A note on extreme points in the closed unit ball of upper triangular 2 × 2 matrices over a C * -algebra
%J Filomat
%D 2022
%P 6767 
%V 36
%N 19
%U http://geodesic.mathdoc.fr/articles/10.2298/FIL2219767T/
%R 10.2298/FIL2219767T
%G en
%F 10_2298_FIL2219767T