(13) Delabarre, Frank A. "Civilisation and Its Effects on Morbidity and Mortality," Journal of Sociologic Medicine, XIX (1918), 220-23.

(14) Knopf, S. A. "The Effects of Civilisation on the Morbidity and Mortality of Tuberculosis," Journal of Sociologic Medicine, XX (1919), 5-15.

(15) Giddings, Franklin H. "The Ethics of Social Progress," in the collection Philanthropy and Social Progress. Seven essays ... delivered before the School of Applied Ethics at Plymouth, Mass., during the session of 1892. With introduction by Professor Henry C. Adams. New York and Boston, 1893.

(16) Morgan, Alexander. Education and Social Progress. Chaps. vi, ix-xxi. London and New York, 1916.

(17) Butterfield, K. L. Chapters in Rural Progress. Chicago, 1908.

(18) Robertson, John M. The Economics of Progress. New York, 1918.

(19) Willcox, Walter F. "A Statistician's Idea of Progress," International Journal of Ethics, XXIII (1913), 275-98.

(20) Zueblin, Charles. American Municipal Progress. Rev. ed. New York, 1916.

(21) Niceforo, Alfredo. Les Indices numérique de la civilisation et du progrès. Paris, 1921.

(22) Todd, A. J. Theories of Social Progress. Chap, vii, "The Criteria of Progress," pp. 113-53. New York, 1918.