Mudgalapurana 2.1.55.c1

2.1.55.c1

oṃ tatsaditi śrīmadāntye purāṇopaniṣadi śrīmanmaudgale mahāpurāṇe dvitīye khaṇḍe ekadantacarite brahmasṛṣṭiprārambho nāma prathamo'dhyāyaḥ ||

Oṃ tat sat. Thus in the glorious last purāṇic upaniṣad, in the venerable Maudgala Mahāpurāṇa, in the second section, in the deeds of Ekadanta, the first chapter, named "The Commencement of Brahmā's Creation".