Bilal Yousuf, Sadia Abdul Qayyum, Syed Mukkaram Ali, Summaiya Syed Tariq, and Naveed Ali Qadri, “Helmet Use and Concussion Severity among Two-Wheel Riders: A Retro-spective Study From Karachi.”, j Muhammad Med Coll, vol. 16, no. 02, pp. 147-151, Mar. 2026.