Colo. Rev. Stat. § 29-14-108
All bond anticipation notes and any coupons appertaining thereto issued or purportedly issued prior to July 1, 1981, and all acts or proceedings had or taken or purportedly had or taken prior to said date by or on behalf of public bodies, under law or under color of law, preliminary to and in the authorization, execution, sale, and issuance of all bond anticipation notes, including any coupons appertaining thereto, and the exercise of other powers in this article are validated, ratified, approved, and confirmed by this section except as provided in section 29-14-109, notwithstanding any lack of power, authority, or otherwise, other than constitutional, and notwithstanding any defects and irregularities other than constitutional, in such bond anticipation notes, acts, and proceedings, in such authorization, execution, sale, and issuance, and in such exercise of power; and such bond anticipation notes are and shall be binding, legal, valid, and enforceable obligations of such public body to which they appertain in accordance with their terms and their authorization proceedings.
C.R.S. § 29-14-108