C.R.S. § 39-11-113: Abbreviations, letters, and figures may be used.

In all advertisements for the sale of tax liens on property for delinquent taxes and in entries required to be made by the assessor, county clerk and recorder, treasurer, or other officers in lists, books, rolls, certificates, receipts, deeds, or notices, letters, figures, and abbreviations may be used to denote townships, ranges, sections, parts of sections, lots, blocks, dates and amounts of taxes, delinquent interest, and costs.