I would recommend USAF testimony before Congress and position papers to DoD of the time; Armed Forces Journal reports on the program during that period; Air Force Magazine of the time; virtually every history of the program, the emphasis they put on USAF opposition varies with the article, etc. The late, great Jeff Ethell, in a documentary on the A-10 discussed why prior to Gulf War I the A-10 didn't have much support in the USAF and why they were so eager to get rid of it. Basically, he said that one of the biggest reasons USAF pushed the A-10 initially was as a way to kill the AH-56. When Army went out and canceled it on their own, AF really didn't know what they wanted to do with the Warthog.
Initially AF had no position on AH-56, when its mission was originally mooted as just transport helicopter escort. However, when Army also started talking up that it could kill tanks (with TOW) and provide CAS, AF started complaining that that was THEIR role, no one else should be allowed to play (see: armed OV-10). Then, when the Army [foolishly] let it be known that their tests showed that with the pusher in Beta the Cheyenne could fly an excellent and stable dive bomb profile, they went ballistic.