Tilman Rodenhäuser (International Committee of the Red Cross) has published
Organizing Rebellion: Non-State Armed Groups under International Humanitarian Law, Human Rights Law, and International Criminal Law (Oxford Univ. Press 2018). Here's the abstract:
he number of non-state actors, in the past not accountable for committing international crimes or violating human rights, is proliferating rapidly. Their ways of operating evolve, with some groups being increasingly fragmented and others organizing transnationally or in cyber space. As non-state armed groups are involved in the vast majority of todays armed conflicts and crisis situations, a new and increasingly important question has to be raised as to whether, and at what point, these groups are bound by international law and thereby accountable for their acts.
