Yuga-Vibhāga and Kāla-Pramāṇa
Measures of Time and the Four Yugas
चत्वारि भारते वर्षे युगानि कवयो ऽबुवन् / कृतं त्रेता द्वापरं च कलिश्चेति चतुष्टयम्
catvāri bhārate varṣe yugāni kavayo 'buvan / kṛtaṃ tretā dvāparaṃ ca kaliśceti catuṣṭayam
In Bharata-varsha, the sages have declared four Yugas: Krita, Treta, Dvapara, and Kali—this is the fourfold cycle.