Zolghadr, M., S. Kahrizi, and A. Soltanian. “Research Paper: Lateral Abdominal Muscles Asymmetry in Female Patients With Chronic Non Specific Unilateral Low Back Pain Practicing Hollowing Exercises”. Journal of Modern Rehabilitation, Vol. 11, no. 2, Apr. 2017, pp. 133-9, http://jmr.tums.ac.ir/index.php/jmr/article/view/85.