Matsya Purana 273.41

273.41

saptarṣīṇāmuparye tat smṛtaṃ vai divyasaṃjñayā.
samādivyāḥ smṛtā ṣaṣṭirdivyābdāni tu saptabhiḥ .. 273.40

This is the cycle of the Great Bear, and is remembered as being, according to divine reckoning, 6 divine months and 7 divine years. According to those constellations divine time proceeds by means of the Great Bear, (41a) (Pargiter)