Skandapurana 16.19.78

16.19.78

devakyāṃ vasudevāttu brahmagargapuraḥsaraḥ ..
ekaviṃśatamasyāsya dvāparasyāṃśasaṃkṣaye ..
naṣṭe dharme tadā jajñe viṣṇurvṛṣṇikule svayam .. 78 ..

from Vasudeva upon Devakī, preceded by the divine Garga. / In this twenty-first Dvāpara, at the end of its fraction, / when dharma was destroyed, then Viṣṇu himself was born in the Vṛṣṇi lineage