1. http://www.hrsa.gov/shortage/
2. US Department of Health and Human Services, Health Resources and Services Administration. Designated Health Professional Shortage Areas Statistics, in Fourth Quarter of Fiscal Year 2014, Designated HRSA Quarterly 2014 http://datawarehouse.hrsa.gov/topics/shortageAreas.aspx
3. http://datawarehouse.hrsa.gov/tools/analyzers/hpsafind.aspx
4. http://www.ada.org/en/science-research/health-policy-institute/data-center