Neumann, Franz, author
Signal-Verlag Baden-Baden, 1976
Buku Teks
Gros, Jurgen
Wilhelm Heyne Verlag, 1999
Buku Referensi
Weber, Max, 1864-1920, author
J.C.B. Mohr (Paul Siebeck) Tubingen, 1956
Buku Teks
Hach, Jurgen
Quelle & Meyer , 1980
Buku Teks
Hellack, Georg
Mainz Erasmusdruck 1974
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