Yuga-Vibhāga and Kāla-Pramāṇa
Measures of Time and the Four Yugas
कृष्णपक्षस्त्वहस्तेषां शुक्लः स्वप्नाय शर्वरी / त्रिंशद्ये मानुषा मासाः पित्र्यो मासस्तु सः स्मृतः
kṛṣṇapakṣastvahasteṣāṃ śuklaḥ svapnāya śarvarī / triṃśadye mānuṣā māsāḥ pitryo māsastu saḥ smṛtaḥ
For them, the dark fortnight is as the day, and the bright fortnight is the night of dreaming. Thirty human months are remembered as one month of the Pitṛs.