1. Centers for disease control and prevention https://www.cdc.gov/coronavirus/2019-ncov/symptoms-testing/symptoms.html
2. Corona virus case counts https://www.worldometers.info/coronavirus/country/us/
3. Google mobility data https://www.google.com/covid19/mobility/
4. Johns Hopkins center for systems science and engineering https://systems.jhu.edu/
5. Johns Hopkins university coronavirus map https://coronavirus.jhu.edu/map.html