Throughout a 10-15 year period, I under took research into the UFO and intelligence activities.
My main source used was various sources (which could lead to a paper trail) and the US FOIA. I obtain quite a considerable amount of valuable information via the FOIA, if you know where to look.
Unfortunately now, the quality of the research isn't proving very effective, and is undermined by outlandish conspiracy theories and beliefs, therefore muddying the waters.
There are very few effective and credible researchers now, many of the researchers are trying to prove a belief or a point of view, they are not trying to analyze the information they obtain to provide conclusive objectives. Unbiased analysis is needed.
Unfortunately, the commercial elements come into play, and if unproved and conspiratorial information sells, then in is more so people will produce such information for financial benefit.
The intelligence services are glad the quality of some of the research is poor, they are misleading many into misinformation and disinformation beliefs. So the games continue.