Kauṣītaki (Śāṅkhāyana) Brāhmaṇa 18.3.5

18.3.5

āśvinam anu yat kiṃca dvidevatyam ṛkṣu tad anuvartayet / (soma: aAśvina śastra)

he should pursue in the verses whatever is addressed to dual divinities after the Āśvina;