Shiva Purana
ऋषय ऊचुः केन मानेन कालेस्मिन्नायुस्संख्या प्रकल्प्यते ॥ संख्यारूपस्य कालस्य कः पुनः परमो ऽवधिः ॥ १ ॥
The sages said:— By what unit is the duration of life calculated in Kāla? What is the upper limit of Kāla in the form of number?
english translation
RSaya UcuH kena mAnena kAlesminnAyussaMkhyA prakalpyate ॥ saMkhyArUpasya kAlasya kaH punaH paramo 'vadhiH ॥ 1 ॥
hk transliteration by Sanscript