Marx & Engels Internet Archive: Letters
Marx or Engels to Sorge Correspondence
Marx to Sorge, September 01, 1870
Engels to Sorge, September 12, 1874
Marx to Sorge, September 27, 1877
Marx to Sorge, October 19, 1877
Marx to Sorge, June 20, 1881
Marx to Sorge, December 15, 1881
Engels to Sorge, March 15, 1883
Engels to Sorge, November 11, 1886
Engels to Sorge, January 1, 1888
Engels to Sorge, December 12, 1889
Engels to Sorge, February 8, 1890
Engels to Sorge, April 19, 1890
Engels to Sorge, September 14, 1891
Engels to Sorge, December 31, 1892
Engels to Sorge, January 18, 1893
Engels to Sorge, November 10, 1894