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However , according to Kodin , repatriating the documents meant admitting that they were authentic and that the sensitive materials involving collectivization , terror , and the purges reflected Soviet reality . There has to be something worked out so that the administrative material remains accessible and the other things are not accessible . Argonne will also contribute its advanced materials characterization capabilities such as the Advanced Photon Source , the nation 's most brilliant research X-ray source , to ensure that the superconducting materials are properly fabricated and that the long lengths that are manufactured are uniform in property . Indeed , I was informed at TsKhSD that all post-1952 material pertaining to international relations had been temporarily reclassified . Note that the asteroidal materials we are talking about are , simply , water , nickel-iron metal , hydrocarbons , and silicate rock .