Werner, E. T. C.
George G. Harrap & Co. Ltd., 1922
Buku Teks
Sombart, Werner
Duncker & Humbolt, 1922
Buku Klasik
Sombart, Werner
Dunker & Humblot, 1922
Buku Klasik
Francon, M., author
Row, Peterson, 1961
Buku Teks
Bodley, John H., author
Mayfield Publishing, 1982
Buku Teks