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2. Beyreuther, E. August Hermann Francke. Marburg: Francke-Buchhandlung, 1956.
3. Brown, D. Understanding Pietism, rev. ed. Nappanee: Evangel Publishing House, 1996.
4. Erb, P., ed. Pietists: Selected Writings, with a preface by F. E. Stoeffler. NewYork: Paulist Press, 1983.
5. Forell, G. W Faith Active in Love: An Investigation of the Principles Underlying Luther's Social Ethics. New York: The American Press, 1954.