Federal Republic
Wiesbaden : Wiesbadener Graphische Betriebe GmbH, 1977
Buku Referensi
Heyde, Wolfgang
C.F. Muller Juristischer Verlag, 1999
Buku Teks
Gumpel, Henry J.
Commerce Clearing House, 1969
Buku Teks
Federal Republic of Germany,, 1980
Buku Teks
The Press and Information Office, 1973
Buku Teks