D. Slavkov and S. Troyanova-Slavkova , Trans., “Factors predicting return to work in patients with chronic low back pain”, INS, vol. 58, no. 3, pp. 38–42, Oct. 2026, Accessed: Nov. 03, 2026. [Online]. Available: https://journals.mu-sofia.bg/index.php/ins/article/view/1265