Life, wanderings and labours in Eastern Africa : with an account of the first successful ascent of the equatorial snow mountain, Kilima Njaro, and remarks upon East African slavery

by Charles New, of the late Livingstone search and relief expedition

The Congo Slave State : a protest against the new African slavery ; and an appeal to the public of Great Britain, of the United States, and of the Continent of Europe

by Edmund D. Morel

The new African slavery; or, King Leopold's rule in Africa

by E. D. Morel

The Mozambique and Nyassa slave trade

by Henry E. O'Neill