California Code, Elections Code - ELEC § 342

“Proponent or proponents of an initiative or referendum measure” means, for statewide initiative and referendum measures, the elector or electors who submit the text of a proposed initiative or referendum to the Attorney General with a request that he or she prepare a circulating title and summary of the chief purpose and points of the proposed measure; or for other initiative and referendum measures, the person or persons who publish a notice or intention to circulate petitions, or, where publication is not required, who file petitions with the elections official or legislative body.