I have 40 years of experience, and specialize in the field of taxation with specific knowledge in the areas of federal, state and constitutional law. I have published on such topics as state taxation, Native American taxation and tax policy. I have testified 80 times on topics such as state taxation, constitutional law and tax policy. I have consulted with the Fortune 500, states, and cities, the United States Congress, the United States Treasury, the Department of Justice, the International Monetary Fund, the World Bank, the United Nations, Vietnam, China, the Navajo Nation, the Philippines, Pakistan, India, Zambia, Gambia, and Mexico.