Değer, U., A. A. Dovgoshei, and M. Küçükaslan. “On the Statistical Convergence of Metric-Valued Sequences”. Ukrains’kyi Matematychnyi Zhurnal, Vol. 66, no. 5, May 2014, pp. 712–720, https://umj.imath.kiev.ua/index.php/umj/article/view/2172.