Gray, Richard, 1944-, author
Longman, 1991
Buku Teks
Bury, J.B., author
Random House, [Date of publication not identified]
Buku Teks
Bury, J.B., author
Modern Library, 1913
Buku Teks
2013
Artikel Jurnal
Stauffer, Donald Alfred, author
Princeton University Press, 1941
Buku Teks