“The Effects of Two Different Doses of Spinal Hyperbaric Solution of Ropivacaine in Elderly Patients ”, Ann Med Res , vol. 14, no. 1, pp. 0027–0031, May 2021, Accessed: Apr. 19, 2025. [Online]. Available: http://annalsmedres.org/index.php/aomr/article/view/3145