Соответствующая норма
Practice Relating to Rule 18. Assessment of the Effects of Attacks
Benin’s Military Manual (1995) 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.” 
Benin, Le Droit de la Guerre, III fascicules, Forces Armées du Bénin, Ministère de la Défense nationale, 1995, Fascicule II, p. 6.