Mudgalapurana 2.10.34

2.10.34

hiraṇyaretasaḥ sapta kuśadvīpapateḥ sutāḥ |
vasuśca vasudānaśca dṛḍharucistṛtīyakaḥ ||

The seven sons of Hiraṇyaretas, lord of Kuśadvīpa, are: / Vasu, Vasudāna, and the third, Dṛḍharuci;