Anakkamatee, W., and S. Dhompongsa. 2013. “ON THE MEANS OF PROJECTIONS ON CAT(0) SPACES”. Journal of Nonlinear Analysis and Optimization: Theory & Applications (JNAO) 4 (2):51-59. https://ph03.tci-thaijo.org/index.php/jnao/article/view/2702.