Nahmias, Steven
Irwin/McGraw-Hill, 1997
Buku Teks
Marx, Karl, 1818-1883, author
Foreign Languages Publishing House, 1958
Buku Teks
Riggs, James L., author
John Wiley & Sons, 1970
Buku Teks
Gonzalo Mejia, editor, Nubia Velasco, editor
[, Springer], 2012
eBooks
Artikel Jurnal