Kalkan, N., and A. Karadağ. “Determining the Functional Autonomy Level of Preoperative Elderly Patients: A Turkish Case Study”. Journal of Human Sciences, vol. 14, no. 3, Sept. 2017, pp. 2827-38, https://www.j-humansciences.com/ojs/index.php/IJHS/article/view/4836.