
https://www.census.gov/content/dam/Census/library/publications/2019/demo/p60-266.pdf

https://www.eurofound.europa.eu/sites/default/files/ef_publication/field_ef_document/ef19034en.pdf

https://www.cidrap.umn.edu/sites/default/files/public/downloads/cidrap-covid19-viewpoint-part1.pdf