Allgemeine technische Bibliothek zu Frankfurt am Main. Bücherverzeichnis. Frankfurt 1920. 1920, (Ikke digitaliseret)
Das Wesen des Lichts. Vortrag gehalten in der Hauptversammlung der Kaiser-Wilhelm-Gesellschaft am 28.Oktober 1919. 1920, (Ikke digitaliseret)
Higher production by a bonus on national output. A proposal for a minimum income for all varying with national productivity. 1920, (Ikke digitaliseret)
Catalogue of samples of Indian manufactures and of articles imported by consuming departments of government. 1920, (Ikke digitaliseret)
The commercial year book of the Coventry chamber of commerce. 1920, Hill, H. C., (Ikke digitaliseret)
Commercial year-book of the Leeds incorporated chamber of commerce with classified trade indices 1920, (Ikke digitaliseret)
Betrieb und Bedienung von ortsfesten Viertakt-Dieselmaschinen. 1920, S. Sygall.; Dalog, A., (Ikke digitaliseret)