Shiva Purana
प्रजापतिश्च विष्णुश्च रुद्रस्यैतौ परस्परम् ॥ सृष्टौ परस्परस्यांगादिति प्रागपि शुश्रुम ॥ ७ ॥
We have also heard that Brahmā and Viṣṇu were born of Rudra and created Rudra. Thus they mutually created each other.
english translation
prajApatizca viSNuzca rudrasyaitau parasparam ॥ sRSTau parasparasyAMgAditi prAgapi zuzruma ॥ 7 ॥
hk transliteration by Sanscript