Ramo, Simon
Hill and Wang, 1988
Buku Teks
Johannes M. Bauer, Achim Lang, Volker Schneider, editors
[Springer, ], 2012
eBooks
Goetsch, David L.
Pearson/Prentice Hall, 2004
Buku Teks
edited by Marco R. Di Tommaso and Stuart O. Schweitzer
Edward Elgar, 2005
Buku Teks
Artikel Jurnal