Herbert Buscher, Volkswirt Bobert Dornau, Friedrich Heinemann, Volkswirt jens Kike
Meyers Lexikonverlag, 1999
Buku Referensi
Ropke, Wilhelm
Elsevier , 1947
Buku Teks
Weber, Max, 1864-1920, author
J.C.B. Mohr (Paul Siebeck) Tubingen, 1956
Buku Teks
Storz, Hans-Ulrich
Otto Harrassowitz, 1967
Buku Teks
Baumol, William J., author
Harper & Brother Publisher, 1954
Buku Teks