The following sites serve as indexes to reference material available on the Internet.
- IRS
- State of Oregon Department of Revenue
- Oregon Board of Acountancy
- Oregon State Board of Tax Pratitioners
- Washington State Department of Revenue
- Idaho State Tax Commission
- Portland State University School of Business Administration Post-Baccalaureate Accounting Certificate
- Federation of Tax Administrators (FTA)
- Tax Analysts
- Yahoo: Business and Economy: Taxes
