Erhard, Ludwig, author
George Allen and Unwin, 1954
Buku Teks
Adelman, M.A., author
Johns Hopkins University Press, 1972
Buku Teks
Fischer, Fritz, author
W.W. Norton & Company, 1967
Buku Teks
Heijbroek, A.M.A., author
Rabobank International Group , 1996
Buku Teks
German : Verlag furwirtschaftliche Information
Majalah, Jurnal, Buletin