"Heimatbasis - 18 essays on the homework of mission; Mission in Confrontation with Colonial Thoughts and "Mission under the Inflow of European Civilization - 17 essays; "Church Building from the Gospel in East Africa - 16 Works; "From the Spiritual World of Primitive Peoples of Africa - 10 Works; Excerpts on the Literature and Spiritual World of the Primitives - 15 Works; "Nachschriften von Fricks Kolleg, Marburg 1930; "From the World of the Primitives - 18 Works