Règle correspondante
Practice Relating to Rule 4. Definition of Armed Forces
Indonesia’s Air Force Manual (1990) states that combatants are:
a. Regular troops, i.e. members of the armed forces, consisting of:
1. voluntary troops;
2. compulsory military; and
3. foreigners, including citizens of neutral States, who belong to a belligerent’s armed forces.
b. Militias, i.e. volunteer groups or persons who, being a part of the armed forces, should be considered as regular troops with the status of legal combatant. 
Indonesia, The Basics of International Humanitarian Law in Air Warfare, Indonesian Air Force, 1990, § 21.