Karez Namiq Kakarash, and Vian Afan Naqshbandi. “Comparison Between the Effectiveness of McKenzie Extension Exercises and William Flexion Exercises for Treatment of Acute or Sub-Acute Low Back Pain”. Journal of Population Therapeutics and Clinical Pharmacology, vol. 30, no. 8, Apr. 2023, pp. 123-3, doi:10.47750/jptcp.2023.30.08.013.