There is NONE. But for those who really want to know the true chain of events that lead to the GB authority here is goes.
Russell's time congregations were independent and elected their own elders, etc. People free to belive or not believe Russells teachings. Holy spirt was available to everybody and everybody could learn the bible themselves.
Rutherford took over, he thought he was God himself and his word should be law. He was outraged many challenged his authority. He made claims Christ returned and that since Christ is now ruling, holy spirit is now longer needed. Christ chose the headquarters of the organization, meaning Rutherford himself, and would issue orders through them. IF a person doesn't obey them, they are rejecting Christ and his orders and would die. After Rutherfords 1925 and other failed prophecies, he got real pissed people were leaving and exposing him for a fraud, he made changes to kick out dissenting elders and get more control of elders, congregations, etc.During all this time, NO gb, just Rutherford in full control.
After he died, Knorr took over. Knorr slowly brought back holy spirit and publications ignored Rutherford saying it was done away with and that angels transmit everything or some hidden secret way. Knorr and friend eventually made comments about a GB, and so they had to form one since they talked about it. Also since holy spirit was part of doctrine again, they didn't want to give up power, so holy spirit is back but nobody except them gets it or can understand the bible, because if they tossed rutherfords stuff out the door fully, then anybody can read the bible. So that's how the doctrine got to where it is today.
