Related Rule
Practice Relating to Rule 18. Assessment of the Effects of Attacks
Togo’s Military Manual (1996) states: “Precautions must be taken in order to minimize civilian losses and damage to civilian objects. These precautions include respect for the rules of proportionality.” 
Togo, Le Droit de la Guerre, III fascicules, Etat-major Général des Forces Armées Togolaises, Ministère de la Défense nationale, 1996, Fascicule II, p. 6.