“The effects of sedation with propofol and propofol- ketamin combination on postoperative cognitive function in elderly patients undergoing spinal anesthesia”, Ann Med Res , vol. 28, no. 6, pp. 1201–1205, Jun. 2021, Accessed: Apr. 04, 2025. [Online]. Available: http://annalsmedres.org/index.php/aomr/article/view/3819