Ganeshapurana 2.149.9

2.149.9

na cātra saṃśayaḥ kāryo vismayo vā mune prabhau |
śivādbrahmā ca viṣṇuśca laiṅge jātau nirūpitau ||

Neither doubt nor astonishment should be had in this matter concerning the Lord, O sage: / in the Liṅgapurāṇa, Brahmā and Viṣṇu are recounted as born from Śiva;