Shiva Purana
तत्पशुत्वं परित्यज्य कृत्वा पाशुपतं व्रतम् ॥ पूजनीयो महादेवो लिंगमूर्तिस्सनातनः ॥ २७ ॥
Freed from Paśu-hood, the devotee shall worship the phallic image of Śiva.
english translation
tatpazutvaM parityajya kRtvA pAzupataM vratam ॥ pUjanIyo mahAdevo liMgamUrtissanAtanaH ॥ 27 ॥
hk transliteration by Sanscript