Warneck, J., author
Landsdrukkerij, 1906
Buku Referensi
Hardeland, A.
[publisher not identified], [date of publication not identified]
Buku Referensi
Arndt, Paul, author
Fribourg, 1961
Buku Referensi
Klappenbach, author
Berlin Akademie 1963
Buku Referensi
Grassmann, H.
Wiesbaden Harrassowitz 1955
Buku Referensi