Surya Siddhanta
इत्थम् युगसहस्रेण भूतसम्हारकारकः। कल्पो ब्राह्मम् अहः प्रोक्तम् शर्वरी तस्य तावती ॥
Thus a thousand of the great yugas make a Kalpa, a period which destroys the whole world. It is a day of the God Brahmá, and his night is equal to his day.
english translation
ittham yugasahasreNa bhUtasamhArakArakaH। kalpo brAhmam ahaH proktam zarvarI tasya tAvatI ॥
hk transliteration by Sanscript