Isea Raul, A General Approach to Modeling Covid-19, Journal of Model Based Research, Volume 2, Issue 2, 2023, Pages 1-19, ISSN 2643-2811, https://doi.org/10.14302/issn.2643-2811.jmbr-23-4556. (https://jndc-chemistryarticles.infojmbr/article/1977) Keywords: Covid-19; Origin; Hosts; Reservoir; Immune; Transmission model; SARS-CoV-2 .