421.1. For the purposes of section 421, a printer, manufacturer, owner or radio or television broadcaster shall also, in the case of a private intervenor within the meaning of Division V or the representative of such an intervenor, indicate the authorization number issued under section 457.6.
Where the cost of the writing, object, material, advertisement or publicity referred to in section 421 exceeds $300, the printer, manufacturer, owner or radio or television broadcaster may only mention or, as the case may be, indicate as the person having caused the writing, object, material, advertisement or publicity to be produced, published or broadcast, the name and title of the official agent or deputy official agent of a candidate or party.