He wrote Gramat Volapüka, a grammar of the language completely in Volapük, and a German-Volapük dictionary, Wörterbuch der Weltsprache (World Language Dictionary).
Han skrev Gramat Volapüka, en grammatik af sproget helt i Volapük, og en tysk-volapük ordbog, Wörterbuch der Weltsprache (Verdenssprog ordbog).