Yesil Cinkir, H., and G. Aktas. “Survival Analysis of Single Agent Gemcitabine Therapy in Patients With Metastatic Breast Cancer”. Annals of Medical Research, vol. 26, no. 9, May 2021, pp. 1773-6, http://annalsmedres.org/index.php/aomr/article/view/1741.