Cal. Rev. & Tax. Code § 156

In the assessment, advertisement, and sale of real property for taxes, initial letters, abbreviations, and figures may be used to designate the township, range, section, or part of a section. Any other abbreviations approved by the board may be used if an explanation of them appears on each page of the roll or a reference appears on each page to a list of abbreviations within each volume of the roll, or if the procedure in Section 109.6 is adopted the list of abbreviations used shall be available to the public in the office of the tax collector. Such list of abbreviations shall be furnished to the tax collector by the assessor.