Campos Vallejo, Rolando Martin, and Edison Marcelo Ibarra Rosero. “Incidence of Covid 19- at the Carchi State Polytechnic University before and After the Vaccination Stage”. Tierra Infinita 8, no. 1 (December 6, 2022): 189–198. Accessed December 18, 2025. https://www.revistasdigitalesupeceduec35.biteca.online/index.php/tierrainfinita/article/view/1163.