Richard T. Ely, Socialism : an examination of its nature, its strength and its weakness, with suggestions for social reform http://archive.org/details/socialismanexam02goog (1894)
As quoted in: Charles Austin Beard and Mary Ritter Beard, basic history of the United States http://books.google.gr/books?id=vaQsAAAAMAAJ&q=A, Doubleday, Doran & company, 1944, p. 395.
Richard T. Ely: Citations en anglais
Richard T. Ely, French and German Socialism in Modern Times http://archive.org/details/frenchandgerman00elygoog, 1883, pp. 204–205.