Washington Revised Code Title 29A. Elections § 29A.72.040. Numbering--Transmittal to attorney general

The secretary of state shall give a serial number to each initiative, referendum bill, or referendum measure, using a separate series for initiatives to the legislature, initiatives to the people, referendum bills, and referendum measures, and forthwith transmit one copy of the measure proposed bearing its serial number to the attorney general. Thereafter a measure shall be known and designated on all petitions, ballots, and proceedings as “Initiative Measure No. ․․․․,” “Referendum Bill No. ․․․․,” or “Referendum Measure No. ․․․․.”