A/HRC/37/81 • Independent Expert on the situation of human rights in the Central African Republic • Independent Expert on the situation of human rights in Somalia • Independent Expert on the situation of human rights in the Sudan. 19. Special procedures mandate holders also presented reports of their visits to 13 countries and territories. In addition, the Working Group on Enforced and Involuntary Disappearances presented a follow-up report to its missions to Chile and Spain. 20. The Working Group on Arbitrary Detention presented a report containing its revised methods of work. The Working Group on Enforced and Involuntary Disappearances presented a report on enforced disappearances in the context of migration. The Special Rapporteur on the promotion of truth, justice, reparation and guarantees of non-recurrence presented a global study on transitional justice. 21. The special procedures also presented their communications report, containing communications sent by all mandate holders between 1 March and 31 May 2017. 5