1. Bruce M (1958) The shaping of the modern world, 1870–1914. Random House, New York
2. Bauer L (1935) Leopold the unloved, king of the Belgians and of wealth. Little Brown, Boston
3. Emerson B (1979) Leopold II of the Belgians, king of colonialism. St. Martin’s, New York
4. Depelchin J (1992) From the Congo free state to Zaire 1885–1974. Codesria, Dakar
5. Adams A (1993) The origin and the early development of the Belgium radium industry. Environ Int 19:491–501