Oregon Revised Statutes Occupations and Professions § 673.370

(1) The display or uttering by a person of a card, sign, advertisement or other printed, engraved or written instrument or device, bearing a person's name in conjunction with the words “certified public accountant” or “public accountant” or any abbreviation thereof, shall be prima facie evidence in any action brought under ORS 673.360 or 673.990 that the person whose name is so displayed caused or procured the display or uttering and that the person is an individual or business organization that purports to be authorized to use the words under ORS 673.010 to 673.465.

(2) In any action referred to in subsection (1) of this section, evidence of the commission of a single act prohibited by ORS 673.010 to 673.465 shall be sufficient to justify an injunction or a conviction without evidence of a general course of conduct.