Internal Revenue Service http://www.irs.gov/

Colorado Department of Revenue http://www.revenue.state.co.us/main/home.asp

Colorado Department of Labor and Employment http://www.coworkforce.com/

City and County of Denver "Doing Business"  http://denvergov.org/jump_doing_business.asp

Electronic Federal Tax Payment System (EFTPS)   https://www.eftps.com/eftps/

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