non vedic tribes
https://en.wikipedia.org/wiki/Kikata
books https://www.google.co.in/books/edition/The_Indo_Aryans_of_Ancient_South_Asia/OZ0gAAAAQBAJ?hl=en&gbpv=1&pg=PA333&printsec=frontcover
https://en.wikipedia.org/wiki/The_History_and_Culture_of_the_Indian_People
online vol 1 vedic age https://archive.org/stream/vedicage00bhar/vedicage00bhar_djvu.txt