Akarapatima, R. “The Risk Factors for Spinal Anesthesia-induced Hypotension in Patients Undergoing Hip Fracture Surgery among the Elderly: A Retrospective Cohort Study”. Thai Journal of Anesthesiology, vol. 47, no. 2, Feb. 2021, pp. 85-92, https://he02.tci-thaijo.org/index.php/anesthai/article/view/249143.