Minahan, James B. (10 February 2014). Ethnic Groups of North, East, and Central Asia: An Encyclopedia. ABC-CLIO. p. 205. ISBN 9781610690188. "Living in the high mountain valleys, the Nuristani retained their ancient culture and their religion, a form of ancient Hinduism with many customs and rituals developed locally. Certain deities were revered only by one tribe or community, but one deity was universally worshipped by all Nuristani as the Creator, the Hindu god Yama Raja, called imr'o or imra by the Nuristani tribes."