Règle correspondante
Practice Relating to Rule 14. Proportionality in Attack
Section B. Determination of the anticipated military advantage
According to Nigeria’s Military Manual (1994), the principle of proportionality requires that “incidental civilian casualties and damage which is excessive in relation to the value of the expected result of the whole operation” must be avoided. 
Nigeria, International Humanitarian Law (IHL), Directorate of Legal Services, Nigerian Army, 1994, p. 42, § 11.
(emphasis added)