अग्निनिचयः (Agninichaya) / The Accumulation of Sacred Fire & the Classification of Pitṛs by Time-Order
स्मृता बर्हिषदस्ते वै पितर स्त्वग्निहोत्रिणः / ऋतवः पितरो देवाः शास्त्रे ऽस्मिन्निश्चयं गताः
smṛtā barhiṣadaste vai pitara stvagnihotriṇaḥ / ṛtavaḥ pitaro devāḥ śāstre 'sminniścayaṃ gatāḥ
The Pitara called Barhiṣada are those who perform the agnihotra; and in this śāstra it is firmly concluded that the seasons are Pitara-devas.