Neider, Charles
Routledge and Kegan Paul Ltd, 1949
Buku Teks
Oppenheimer, Franz
Dusseldorf Joseph Melzer Verlag 1964
Buku Teks
Leipzig Koehler & Amelang 1957
Buku Teks
Cameron, Edward A., author
Reynal & Hitchock, 1941
Buku Teks
editor, Wolfgang Kruse
Press and Information Office of Land Berlin, 1979
Buku Teks