I use a number of archive sources on this blog. Here is where they come from:
CAMD RF (ЦАМО РФ): Central Archive of the Ministry of Defense of the Russian Federation. The archive has existed since 1936, and contains over 17 million items. Physically located in Podolsk. This archive, among many things, contains blueprints, proposals, and reports related to tanks, and, as such, is my most frequently used source.
RGVA (РГВА): Russian Government Military Archives. Established in 1920. This archive contains documents pertaining to the history of the Red Army and the MVD/NKVD, as well as foreign documents imported into the USSR. Physically located in Moscow. This archive does not deal with tank-related materials very often, and is not frequently referenced by my blog.
RGVIA (РГВИА): Russian Government Military-Historical Archive. Established in 1797. Contains documents dealing with the Imperial Russian military until 1918. Its documents of interest concern the earliest tanks and armoured cars. Physically located in Moscow.
RGASPI (РГАСПИ): Russian Government Archive for Socio-Political History. Of the archives used by this blog, it is both the youngest (established in 1999) and has the oldest documents (dating back to 1617). Of course, I don't use materials that old. Physically located in Moscow. Again, tanks are not the focus of this archive, but there are associated documents, such as meeting minutes and purchase orders. Parts of the RGASPI archive are available online at "Documents of the Soviet Era".
TsDOOSO (ЦДООСО): Documentation Center of Sverdlovsk Region Public Organizations. The archive does not have anything to do with tanks specifically, but the city is home to NII-48, and it contains documents pertaining to it.
GKO/GOKO Decrees: A list of all decrees (and scans or instructions on where to find some) is available here.
RGANTD (РГАНТД): Russian Government Archive of Scientific and Technological Documents. The archive began its life as an aerospace archive in 1974, and was rearranged into a general technical documentation archive in 1995. This archive absorbed technical documents from the Defense Production archive. Due to its close ties with rocketry, this archive contains a wealth of materials on the Katyusha rocket artillery system. Physically located in Moscow.
NARA: National Archives and Records Administration. An American archive agency containing, among other items, German captured documents. Physically located in various locations.
DTIC: Defense Technical Information Center. Physically located in the United States, but offers a great wealth of declassified Department of Defense materials online.
FOIA: The Freedom of Information Act passed in the United States declassifies many documents. A large amount of tank related documents may be found through FOIA search and the CIA Electronic Reading Room.
GAO: Government Accountability Office. Provides data on US Government programs, including tank development.