Mudgalapurana 3.15.3

3.15.3

varṇāśramavibhāgaṃ vai svasvācārasamanvitam |
yugamānaṃ tathā vipro yugadharmān viśeṣataḥ ||

the division of the classes and stages of life endowed with their respective proper conduct, / the measure of the yugas, O twice-born, and especially the dharmas of the yugas;