Cal. Elec. Code § 13308

In addition to the restrictions set forth in Section 13307, any candidate’s statement submitted pursuant to Section 13307 shall be limited to a recitation of the candidate’s own personal background and qualifications, and shall not in any way make reference to other candidates for that office or to another candidate’s qualifications, character, or activities. The elections official shall not cause to be printed or circulated any statement that the elections official determines is not so limited or that includes any reference prohibited by this section.