Coba jelasin Sumber-sumber primer dari Negara Bebas Kongo dong

Ó Síocháin, Séamas dan Michael O’Sullivan, eds: The Eyes of Another Race: Roger Casement's Congo Report and 1903 Diary. University College Dublin Press, 2004. ISBN 1-900621-99-1.

Stanley, Henry Morton, The Congo and the Founding of the Congo Free State (London, 1885)

Report of the British Consul, Roger Casement, on the Administration of the Congo Free State, dicetak ulang secara penuh dalam The eyes of another race: Roger Casement’s Congo report and 1903 diary diedit oleh Seamas O Siochain dan Michael O'Sullivan. Dublin, 2003.

Laporan dari Asosiasi Reformasi Kongo, khususnya "Memorial on the Present Phase of the Congo Question" (London, 1912).

The Congo Report of Commission of Inquiry (New York, 1906)