*Mary Hegeler Carus's extant personal papers are housed at the Special Collections Research Center, Southern Illinois University Carbondale, and The Hegeler Carus Mansion in La Salle, IL.
Carus, Kate B. “Mary Hegeler Carus: An Accidental Engineer.” Paper presented at the 1999 International Symposium on Technology and Society, New Brunswick, NJ, July 1999.
Edward Hegeler-Paul Carus Family Papers. Southern Illinois University Carbondale, Morris Library.
Hegeler, Erich H. Die Delmenhorster Ratsfamilie – Hegeler, 1428–1952. Bremen: Hauschild, 1952.
Hegeler Carus, Mary. Correspondence. The Hegeler Carus Mansion, La Salle, IL.
Henderson, Harold. Catalyst for Controversy: Paul Carus of Open Court. Carbondale: Southern Illinois University Press, 1993.
Lenzi, Michael E. “Zinc Comes to LaSalle and Peru: A Historical Geography of the Matthiessen and Hegeler Zinc Company and the Midwestern Zinc Industry.” In The Industrial Revolution in the Upper Illinois Valley, edited by Michael P. Conzen, Glenn M. Richard, and Carl A. Zimring, 119–34. Chicago: The University of Chicago, 1993.
Lohne, Raymond. “Mary Hegeler Carus (1861–1936).” Immigrant Entrepreneurship: Great American Business Biographies, 1720 to the Present. Last modified November 15, 2013. http://immigrantentrepreneurship.org/entry.php?rec=109.
McKeown, Adam M. “The Expansion and Philanthropy of the Matthiessen and Hegeler Business Interests, 1871–1972.” In The Industrial Revolution in the Upper Illinois Valley, edited by Michael P. Conzen, Glenn M. Richard, and Carl A. Zimring, 135–49. Chicago: The University of Chicago, 1993.
Singer, Sandra L. Adventures Abroad: North American Women at German-Speaking Universities, 1868–1915. Westport: Praeger, 2003.
Smith, David Eugene. “Mary Hegeler Carus, 1861–1936.” The American Mathematical Monthly 44, no. 5 (1937): 280–83.
Sugden, Sherwood J. B. “Historical Introduction.” In Open Court: A Centennial Bibliography, 1887–1987, ed. Ralph E. McCoy, 11–26. La Salle: Open Court Publishing Company, 1987.