Santayana: Winds of Doctrine, 1913, pp. 39-46.

Santayana: Egotism in German Philosophy, 1917, pp. 1 ff., 23.

P. Imbart de la Tour: Les Origines de la Réforme, 3 vols. 1905-13.

P. Imbart de la Tour: "Luther et l'Allemagne," in Revue de métaphysique et morale, 1918, p. 611.

David J. Hill: A History of Diplomacy in the International Development of Europe, vol. 2, 1906, pp. 422 f, 460.

A. W. Benn: A History of English Rationalism in the Eighteenth
Century
, 1906, pp. 76 f.

J. Mackinnon: A History of Modern Liberty, Vol. iii, The Age of the
Reformation, 1906.

T. M. Lindsay: A History of the Reformation. 2 vols. 1906-7.

H. Böhmer: Luther im Lichte der neueren Forschung. 1906. (2d. ed. 1909, 3d. 1913, 5th 1918, each much changed).

Ernst Troeltsch: Bedeutung des Protestantismus für die Entstehung der modernen Welt. 1906. (2d ed. 1911; English translation, "Protestantism and Progress." 1912).