If you know of any such collection, please let me know. I would be very interested in inspecting it. Oral histories may also contain UFO related material. During 1947 radio was a big part of peoples' lives. Much UFO lore must have come from the radio.
Some radio stations have archives of local news stories they ran.
Also, there are several national organizations which might have archives. The same is true of the movie newsreels. No doubt I have missed several good sources of information or obvious ideas. Please let me have your input here.