Seiffert, Leslie
W. Kohlhammer, 1968
Buku Teks
Krause, F. E. A., author
Verlag Erust Reinhardt, 1924
Buku Referensi
Wasserzieher, Ernst
Ferd Dummlers Verlag, 1966
Buku Referensi
Kluge, Friedrich, 1856-1926, author
Walter De Gruyter, 1963
Buku Referensi
Wilss, Wolfram, author
Gunter Narr, 1986
Buku Teks