There may or may not be something of interest in the documents released by the National Intelligence Council, representing some of the intelligence estimates on Yugoslavia prepared for US agencies between 1948 and 1990. What may be most interesting of all is the introductory essay to the collection by Marten H.A. van Heuven, attempting to assess just where intelligence succeeded and failed, and noting the strong and perhaps excessive emphasis placed on trying to understand Yugoslavia through the lens of the Soviet Union.
Related?: The CIA's role in the publication of Dr Zhivago?