Martínez-Serrano, Maria, et al. “Characterization of Humoral Response After COVID-19 Infection in an Unvaccinated Cohort”. Archives of Clinical and Biomedical Research, vol. 5, no. 6, Dec. 2021, pp. 959-71, https://fortunejournals.org/ojs/index.php/acbr/article/view/14881.