Castro-Torres, Yaniré, Estela S. Estapé, María T. San Martín, and Deana Hallman. 2023. “COVID-19 Serological Study in Non-Infected Vaccinated Subjects: Differences Among Age, Sex, and Vaccine Brand”. Puerto Rico Health Sciences Journal 42 (3):203-6. https://prhsj.rcm.upr.edu/index.php/prhsj/article/view/3098.