This in-depth piece by UFO scholar Richard Dolan analyzes twelve government documents that mention various UFO cases and incidents. These are real gems including the FBI memo of 1949, the Minot and Malstrom Air Base incidents in the 1960’s, and the Halt memo from the Rendlesham Forest case of 1981, and the Belgium Triangles in 1989-90. The Coast Guard case from Lake Erie in 1988 is particularly fascinating. Document viewing links do not seem to work but you can read the excerpts. (Thanks to @IQXS for this one.)