Routledge, 1997
Buku Referensi
Haensch, Gunther, author
BLV Verlagsgesellschaft, 1987
Buku Referensi
Affentranger, Christoph
Birkhal'user, 1997
Buku Teks
by Johannes Hochtl ...[and others]
Verlag Enzyklopadie Leipzig, 1960
Buku Referensi
Hartley, Paul, author
Companion Website, 2006
Buku Teks