Manuals and operating instructions for old Soviet cars - ZiL, "Moskvich", "Volga" and others were found in the document archive of the Central Intelligence Agency (CIA) of the USA.
According to the description, the documents were received by the department back in the 1960s and were kept in restricted access with the "confidential" mark for decades.
The catalog of spare parts for the GAZ-21 with a volume of 263 pages was published in 1960 by the "Avtoexport" association for buyers of Soviet cars abroad. The book was printed only in Russian, but without any level of secrecy.
The directory received the "Secret" stamp in the CIA and was stored with it in a closed archive for half a century until 2012. Probably, during the Cold War, the CIA collected any information about a likely adversary that it could get.