(11) Huot, Louis, and Voivenel, Paul. Le Courage. Paris, 1917.

(12) Porter, W. T. Shock at the Front. Boston, 1918.

(13) Lord, Herbert Gardiner. The Psychology of Courage. Boston, 1918.

(14) Hall, G. Stanley. Morale, the Supreme Standard of Life and Conduct. New York, 1920.

(15) Roussy, G., and Lhermitte, J. The Psychoneuroses of War. Translated by W. B. Christopherson. London, 1918.

(16) Babinski, J. F., and Froment, J. Hysteria or Pithiatism, and Reflex Nervous Disorders in the Neurology of the War. Translated by J. D. Rolleston, with a preface by E. Farquhar Buzzard. London, 1918.

2. The Natural History of War:

(1) Sumner, William G. War and Other Essays. Edited with an introduction by Albert Galloway Keller. New Haven, 1911.

(2) Letourneau, Ch. La Guerre dans les diverses races humaines. Paris, 1895.

(3) Frobenius, Leo. Weltgeschichte des Krieges. Unter Mitwirkung von Oberstleutnant a. D. H. Frobenius u. Korvetten-Kapitän a. D. E. Kohlhauer. Hannover, 1903.