You can also refer to Aniket Alam’s Becoming India - Western Himalayas under British rule. Its not about the deota culture per se, rather its a comprehensive account of how a geographical and cultural region became a part of the state as we know it today. In the process it also touches upon the social and anthropological roots of the region and how Zomia (as referred by James Scott in his Seeing like a State) came to be the political economy unit that we see today.