Shiva Purana
एवं लब्धवरो व्यासो महेशान्मध्यमेश्वरात॥ अष्टादश पुराणानि प्रणिनाय स्वलीलया ॥ ११९ ॥
Vyāsa who thus secured the boon from the great lord Madhyameśvara composed the eighteen Purāṇas sportively.
english translation
evaM labdhavaro vyAso mahezAnmadhyamezvarAta॥ aSTAdaza purANAni praNinAya svalIlayA ॥ 119 ॥
hk transliteration by Sanscript