Shiva Purana
ऋषय ऊचुः ॥ भगवञ्छ्रोतुमिच्छामो व्रतं पाशुपतं परम् ॥ ब्रह्मादयो ऽपि यत्कृत्वा सर्वे पाशुपताः स्मृताः ॥ १ ॥
The sages said:— O holy lord, we wish to hear of the great Pāśupatavrata on performing which Brahmā and others have become Pāśupatas.
english translation
RSaya UcuH ॥ bhagavaJchrotumicchAmo vrataM pAzupataM param ॥ brahmAdayo 'pi yatkRtvA sarve pAzupatAH smRtAH ॥ 1 ॥
hk transliteration by Sanscript