forward progress when caught in the air

[kdf5]

Robert, my argument is based on the following rules:

2-34-1...A ball in player possession is a live ball held or controlled by a player after it has been handed or snapped to him, or after he has caught or recovered it.

2-4-1...A catch is the act of establishing player possession of a live ball which is in flight, and first contacting the ground inbounds or being contacted by an opponent in such a way that he is prevented from returning to the ground inbounds while maintaining possession of the ball.

8-2...Possession of a live ball in the opponent’s end zone is always a touchdown.

The only rule I can't find is the one that says "possession is retroactive to when the ball was actually grasped by the airborne player". Please give me the rule number for that statement.