A proof that mixed strategies need not be considered in certain duel situations, provided there may be a continuously variable rate of fire.
Shapley, Lloyd S., Note on Duels with Continuous Firing. Santa Monica, CA: RAND Corporation, 1949. https://www.rand.org/pubs/research_memoranda/RM118.html. Also available in print form.
Shapley, Lloyd S., Note on Duels with Continuous Firing, Santa Monica, Calif.: RAND Corporation, RM-118-PR, 1949. As of September 08, 2021: https://www.rand.org/pubs/research_memoranda/RM118.html