Qian, Mei-ping, Mei-rong Dong, Fang Kang, and Juan Li. “Effect of the Duration of Chronic Low Back Pain on Pain Sensitivity of Patients Undergoing Lumbar Fusion Surgery”. Pain medicine 5, no. 4 (March 11, 2021): 8–15. Accessed April 10, 2021. https://painmedicine.org.ua/index.php/pnmdcn/article/view/237.