Centers for Medicare and Medicaid Services. (2005). CMS plans for transitioning to the National Provider Identifier (NPI) in the fee-for-service Medicare program. Retrieved July 1, 2005, from http://www.cms.hhs.gov/providers/npi.pdf
2.
Department of Health and Human Services. (2004, January). HIPAA administrative simplification: Standard unique health identifier for health care providers. Federal Register, 69(15), 45 CFR, Part 162.