CBF Church (House of Worship)
http://www.cbf-online.org/telugubooks.htm
This website has the online Telugu Bible.
Horeb House of Worship
http://www.horebchurch.com/books.html
I think this website has books by Bakht Singh.
The Christian Messenger
http://thechristianmessenger.blogspot.in/p/brobakth-singh.html
http://thechristianmessenger.blogspot.in/
I think this website has books by Bakht Singh.