1. Bernard, 1971. Sermons on the song of songs, vol. I, 16. Spencer, Mass.: Cistercian Publications.
2. Beuhler, P.T. 1942. Anfechtung bei Luther. Zurich.
3. Dilthey, Wilhelm. 1988. Introduction to the human sciences (trans: Betanzos, Ramon J.). Detroit: Wayne State University Press (original published 1922).
4. Eckhart, M. 1981. The essential sermons, treatises, commentaries, and defense. New York: Paulist Press.
5. Gerrish, B.A. 1962. Grace and reason: A study in the theology of Luther. Oxford: Oxford University Press.