C.R.S. § 24-12-108: Tax returns - applications for refunds.

Any person required to make any return or any application for refund or protest against any deficiency assessment involving any tax imposed by the sales, use, income, motor fuel, and motor vehicle tax laws under oath or affirmation, in lieu of such oath or affirmation, may make a written verification or declaration that it is true and correct and that it is made under the penalties of perjury in the first degree, and the same is valid and complete without any attestation before a notary public or other officer if the signature thereto is witnessed by a legally competent person.