The resources below are books, articles, and other media that are useful references for aspects of this topic. When they are complete, each reference will be described and tagged. See here for an example of a more or less complete entry.
Conley, Jerome M. "Nuclear Command and Control in the Twenty-First Century: Trends, Disparities, and the Impact on Stability." In Debating 21st Century Nuclear Issues, edited by Owen Price and Jenifer Mackby, 226-250. Washington, D.C.: Center for International and Strategic Studies, 2007. https://www.csis.org/analysis/debating-21st-century-nuclear-issues.
Giles, Gregory F. "Safeguarding the Undeclared Nuclear Arsenals." The Washington Quarterly 16, no. 2 (spring 1993): 173-186. https://doi.org/10.1080/01636609309443403.
Slocombe, Walter B. Democratic Civilian Control of Nuclear Weapons. Policy Paper no. 12. Geneva: Geneva Centre for the Democratic Control of Armed Forces (DCAF), 2006. https://www.dcaf.ch/sites/default/files/publications/documents/pp12_democratic_civilian_control_nuclear_weapons.pdf.