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.
Burr, William. Presidential Control of Nuclear Weapons: The "Football." Briefing Book #632. Washington, D.C.: National Security Archive, 2018. https://nsarchive.gwu.edu/briefing-book/nuclear-vault/2018-07-09/presidential-control-nuclear-weapons-football.
Hoffman, David E. "The Russian Nuclear Button: New questions about the Soviet legacy of three briefcases." Foreign Policy. May 27, 2010. https://foreignpolicy.com/2010/05/27/the-russian-nuclear-button-2/.
Lewis, Patricia, Heather Williams, Benoît Pelopidas and Sasan Aghlani. Too Close for Comfort: Cases of Near Nuclear Use and Options for Policy. London: Chatham House, 2014. https://www.chathamhouse.org/sites/default/files/field/field_document/20140428TooCloseforComfortNuclearUseLewisWilliamsPelopidasAghlani.pdf.
Podvig, Pavel. "History and the Current Status of the Russian Early-Warning System." Science and Global Security 10 (2002): 21-60. https://cisac.fsi.stanford.edu/publications/history_and_the_current_status_of_the_russian_earlywarning_system.
Podvig, Pavel. "Risks of Nuclear Command and Control Accidents." In Understanding Nuclear Risks, edited by John Borrie, Tim Caughley, and Wilfred Wan, 53-59. Geneva, Switzerland: United Nations Institute for Disarmament Research (UNIDIR), 2017. http://www.unidir.org/files/publications/pdfs/understanding-nuclear-weapon-risks-en-676.pdf.