Bello-Villanueva, Ana Mercedes, et al. “Characteristics of Pain, Psychological Aspects, Quality of Life and Coping Strategies in Patients With Chronic Back Pain in a City of Colombia”. Colombian Journal of Anesthesiology, vol. 45, no. 4, Oct. 2017, pp. 310–316, https://www.revcolanest.com.co/index.php/rca/article/view/557.