Levels of Some Blood Clotting Factors in COVID-19 Patients: Comparative Study Before and After Pfizer- BioNTech Vaccinations. Iraqi Journal of Science [Internet]. 2023 Oct. 30 [cited 2024 May 20];64(10):4911-7. Available from: https://ijs.uobaghdad.edu.iq/index.php/eijs/article/view/7762