457.18. A private intervenor who is an elector or the representative of a private intervenor shall, within 30 days after polling day, file with the chief electoral officer a report of all the private intervenor’s expenses, in the form prescribed by the chief electoral officer.
The report must be accompanied with the invoices, receipts and other vouchers, or certified copies of those documents, a list thereof and a sworn declaration in the prescribed form.