Fly Ball Assist

[JamesV]

R1 on First. Batter hits fly ball toward F7.
Ball hits F7's glove and is caught by F8 who was in the area. R1 heads to 2nd Base as soon as ball his F7's glove.
After F8 catches the ball, she throws to F3 who tages 1st Base, appealing that R1 left early.

Umpire calls R1 out for leaving early and will not listen to coach who states that the runner is released after the ball touches a fielder.

What is ASA reference indicating that this was an assist not a caught ball?
Thanks
Jim