California Code, Elections Code - ELEC § 10704

(a) Except as provided in subdivision (b), a special primary election shall be held in the district in which the vacancy occurred on the 9th Tuesday or, if the 9th Tuesday is the day of or the day following a state holiday, the 10th Tuesday preceding the day of the special general election at which the vacancy is to be filled.  Candidates at the primary election shall be nominated in the manner set forth in Chapter 1 (commencing with Section 8000) of Part 1 of Division 8, except that nomination papers shall not be circulated more than 73 days before the primary election, shall be left with the county elections official for examination not less than 53 days before the primary election, and shall be filed with the Secretary of State not less than 53 days before the primary election.

(b) A special primary election shall be held in the district in which the vacancy occurred on the 10th Tuesday preceding the day of the special general election at which the vacancy is to be filled if both of the following conditions apply:

(c) The sample ballot for a special election shall contain a written explanation of the election procedure for voter-nominated office as specified in subdivision (b) of Section 9083.5.  Immediately after the explanation shall be printed the following:  “If one candidate receives more than 50% of the votes cast at the special primary election, the candidate will be elected to fill the vacancy and no special general election will be held.”

(d) On the ballot for a special election, immediately before or above the first contest for a voter-nominated office, the following words shall be printed:

“Voter-Nominated Offices

All voters may vote in these contests.

Candidates display a party preference (or None) for the information of voters.  This is not a party endorsement or approval.”