Correspondence (s.a. M 270), 1896-1897; correspondence, reports, diary excerpts (s.a. M 273) from 1906; Easter sermon in Hohenfriedeberg, 1914; "Vom Schulbau in Mutindili, 1914; Letters by Elfriede Kraemer (stepdaughter of Hosbach) to the Trittelvitz couple, 1912-1914; Hosbach's letters from prisoner of war in Egypt, 1917-1919; "Paulo Shempahila - Lebensbild eines einheimischen Gehilfen, 1919; 3 Songs in Swaheli (Text u. Sheet music by Martha Hosbach), 1927; Letters and reports by Martha Hosbach from 1926; "Die Schule von Kijunga von Josua Hermas, translated by Wilhelm Hosbach, 1932; Jahres-, Konferenz- u. Schulberichte von Bukoba, 1932; Gutachten zur Wasserversorgung in Kigarama, 1932; draft: "Integration of the mission into the German Protestant Church of Knak; "Neue Ordnung für die Missionsarbeiter der Bethel-Mission, 1933; "Ein Wort Dankbarer Erinnerung an Frau Künzel, 1934; Correspondenz während des 2. 1939-1949; letter from an African teacher to Wilhelm Hosbach, 1949; correspondence with the Hosbach couple at home, 1949-1961; obituary for Martha Hosbach, widowed Kraemer, née Wegener; obituary, obituary and memories of Wilhelm Hosbach, 1964

Curriculum Vitae and Testimonies, 1929; Instructions and Vows of Deputation, 1930; Correspondence (also during internment), 1929-1947; Photo by Werner Wittenberg, 1930; Certificate of Good Conduct and Medical Certificate by Werner Wittenberg, 1932; "Jubilee of the Bukoba Church on 28.07.1935; "Etwas vom Gelde im Haya-Lande, 1936; "From the work of the mission office in Bukoba, 1937; Correspondence during the stay in Queenstown in South Africa, 1947-1956; Correspondence with Hanni Wittenberg about supply matters, 1956-1965