“Evaluating the Effectiveness of Pfizer, AstraZeneca, and Sinopharm Vaccines Against COVID-19 in Iraq: A Cross-Sectional Study of Vaccine Efficacy and Symptom Severity”. 2024. Journal of Madenat Alelem 16 (1): 11-21. https://journal.mauc.edu.iq/index.php/JMAUC/article/view/507.