Shiva Purana
तत्सान्निध्यं भैरवोऽपि कालोऽभूत्कालकालनः ॥ स देवदेववाक्येन बिभ्रत्कापालिकं व्रतम् ॥ २ ॥
Due to Brahmahatyā’s presence Bhairava began to calculate the time for release. At the words of the lord of gods, he kept on the rite of Kāpālika.
english translation
tatsAnnidhyaM bhairavo'pi kAlo'bhUtkAlakAlanaH ॥ sa devadevavAkyena bibhratkApAlikaM vratam ॥ 2 ॥
hk transliteration by Sanscript