Kauṣītaki (Śāṅkhāyana) Brāhmaṇa 30.2.18

30.2.18

gāyatrīṣu maitrāvaruṇāya praṇayanty uṣṇikṣu brāhmaṇācchaṃsine anuṣṭupsv acchāvākāya uttara uttaritāyai / (soma: hotraka śastrāṇi(tṛtīya savanam))

They bring forward [verses] in Gāyatrī for the Maitrāvaruṇa, in Uṣṇih for the Brāhmaṇācchaṃsin, and in Anuṣṭubh for the Acchāvāka, for the sake of higher and higher [eminence].