This primary source comes from the Records of the Central Intelligence Agency.
Full Citation: USSR Nuclear Weapon Stockpile Sites and Long-Range Bomber Deployment; Published Maps, 1947 - 2015; Records of the Central Intelligence Agency, Record Group 263; National Archives at College Park, College Park, MD. [Online Version, https://docsteach.org/documents/document/ussr-nuclear-weapon-stockpile-sites-and-longrange-bomber-deployment, May 13, 2024]