Matsyapurana 17.25

17.25

pitṝn āvāhayiṣyāmi kurvityuktastu taiḥ punaḥ
uśantastvā tathāyantu ṛgbhyām āvāhayetpitṝn //

Then the worshipper should say, "Pitrînâvâhaiśyami," [I shall now invoke the pitṛis] when the assembled priests [Brâhmaṇas] permit him by saying "Kuru." Afterwards, the worshipper should say, "Uśantastvâ," "Âyentuvah Pitaraḥ," and thus invoke the Pitṛis with these two Ṛig Verses.—25.