Shiva Purana
व्रतं पाशुपतं कृत्वा त्वथर्वशिरसि स्थितम् ॥ भस्मसंछन्नसर्वांगा बभूवुरमरास्तदा ॥ १८ ॥
After observing the vow of Pāśupata, he placed the Atharva Veda on his head. Then the immortals became all covered with ashes.
english translation
vrataM pAzupataM kRtvA tvatharvazirasi sthitam ॥ bhasmasaMchannasarvAMgA babhUvuramarAstadA ॥ 18 ॥
hk transliteration by Sanscript