Farrington, Karen, author
Chancellor Pres, 1998
Buku Referensi
Seo, Myengko, author
Routledge, Taylor & Francis Group, 2013
Buku Teks
Risjord, Norman K., author
Prentice-Hall, 1985
Buku Teks
Williams, T. Harry, author
Alfred A. Knopf, 1963
Buku Teks
Beard, Charles A., author
New Home Library, 1944
Buku Teks