Jansen, Axel: Heroes or Citizens: The 1916 Debate on Harvard Volunteers in the European War, in: Krüger, Christine G. / Levsen, Sonja (eds.): War volunteering in modern times: from the French Revolution to the Second World War, Houndmills, Basingstoke, Hampshire ; New York, NY 2011 Palgrave Macmillan, pp. 150-162.