1. Topic: GDP of Worldhttps://data.worldbank.org/indicator/NY.GDP.MKTP.KD.ZG?end=2020&start=1961&view=chart
2. Topic: COVID-19 Caseshttps://covid19.who.int/
3. Topic: Approved Vaccineshttps://covid19.trackvaccines.org/agency/who/
4. Topic: Countries with Vaccinehttps://www.who.int/
5. The SIR model and the foundations of public health;Weiss;Mater. Math.,2013