Colo. Rev. Stat. § 31-16-202
If all the procedures and requirements of this part 2 are complied with, any municipality may enact any ordinance which adopts any code by reference in whole or in part, and such primary code thus adopted may in turn adopt by reference, in whole or in part, any secondary codes duly described therein. However, every primary code which is incorporated in any such adopting ordinance shall be specified in the title of the ordinance. Notwithstanding the procedures and requirements of this part 2, a municipality may enact any ordinance which adopts by reference any statute, rule, regulation, or standard adopted by the federal government or the state of Colorado, or by any agency of either of them, solely by referring to such statute, rule, regulation, or standard in the text of such ordinance.
C.R.S. § 31-16-202
This section is similar to former § 31-12-402 as it existed prior to 1975.