Yuga-Vibhāga and Kāla-Pramāṇa
Measures of Time and the Four Yugas
ऋषिवंशप्रसंगेन व्याकुलत्वात्तथैव च / अत्र त्रेतायुगस्यादौ मनुः सप्तर्षयश्च ये
ṛṣivaṃśaprasaṃgena vyākulatvāttathaiva ca / atra tretāyugasyādau manuḥ saptarṣayaśca ye
Stirred by the account of the lineage of the seers, here, at the dawn of the Tretā Yuga, Manu and the Seven Ṛṣis who were present are spoken of.