Tetiana –íludova, Nataliia Savchuk, Nadiia Skliar, Svitlana Usherenko, Pavlo Verba. (2020). Cyclical Behavior and Connection between Recovered and Sick COVID 19 Patients Worldwide. International Journal of Advanced Science and Technology, 29(3), 11970 -. Retrieved from https://sersc.org/journals/index.php/IJAST/article/view/29888