Handbuch der Ful-Sprache; Wörterbuch, Grammatik übungen und Texte, Berlin: D. Reimer, 1909 California
Die Sprache der Haussa in Zentralafrika, Berlin: D. Reimer (E. Vohsen), 1911
A short grammar of the Shilluk language, Philadelpha, PA: The Board of foreign missions of the United Presbyterian church of N.A.; Berlin: D. Reimer (E. Vohsen), 1912, Internet Archive
Diedrich Westermann, Ida C. Ward, Practical phonetics for students of African languages, International African Institute, Oxford University Press, 1933 Virginia, Internet Archive
Dietrich Westermann, M. A. Bryan, The languages of West Africa, Handbook of African languages, Part II, Oxford University Press, International African Institute, 1952 Internet Archive