Rasheed, Saad Mubarak, et al. “Results and Predictive Factors for Single Level L4-5, and L5-S1 Disc Herniation Surgery”. AL-Kindy College Medical Journal, vol. 11, no. 2, Dec. 2015, pp. 55-63, https://jkmc.uobaghdad.edu.iq/index.php/MEDICAL/article/view/373.