Kounchev, Ognyan, Georgi Boyadzhiev, Georgi Simeonov, Methody Kunchev, and Zhana Kuncheva. “SEIR Model Analysis of the Omicron Variant Spread in Bulgaria – an Empirical Study”. Proceedings of the Bulgarian Academy of Sciences 76, no. 1 (January 30, 2023): 114–119. Accessed February 27, 2024. https://proceedings.bas.bg/index.php/cr/article/view/239.