Shiva Purana
व्रतमेतत्करोमीति भवेत्संकल्प्य दीक्षितः ॥ यावच्छरीरपातं वा द्वादशाब्दमथापि वा ॥ ७ ॥
After resolving to observe this vow one should be initiated Until the fall of the body or for twelve years.
english translation
vratametatkaromIti bhavetsaMkalpya dIkSitaH ॥ yAvaccharIrapAtaM vA dvAdazAbdamathApi vA ॥ 7 ॥
hk transliteration by Sanscript