For all of the papers listed above, two publications are useful. The first is United States Air Force History: A Guide to Documentary Sources (Washington, D.C., 1973) , compiled by Lawrence J. Paszek; full text available online (https://hdl.handle.net/2027/mdp.39015034716574). The other is Personal Files in the US Air Force Historical Collection (Albert F. Simpson Historical Research Center, 1975), pamphlet, 29 pp.
According to Mr. James Eastman, Chief of the Research Branch, "Spread throughout our collection is material concerning the transfer, delivery, and supply of lend-lease aircraft to the Russians in World War II. Also data are included in HQ army air force and various bomb unit records and periodic histories on Operation Frantic—the use of Russian bases for shuttle-bombing Germany in 1944." For some possible further leads, the researcher might wish to consult the bibliography in Richard C. Lukas, Eagles East: The Army Air Forces and the Soviet Union, 1941–1945 (Tallahassee: Florida State University Press, 1970).