Die Lehre der Zwölf Apostel

History of Dogma; Volume 3

Monasticism : Its Ideals and History, and the Confessions of St. Augustine

The Mission and Expansion of Christianity in the First Three Centuries; Volume 2

History of Dogma; Volume 7

History of Dogma; Volume 1

History of Dogma; Volume 3

History of Dogma; Volume 7

Wesen des Christentums

Geschichte der Königlich Preussischen Akademie der Wissenschaften Zu Berlin, Volume 1, Part 1

History of Dogma; Volume 1