Vox, author
McGraw-Hill, 2012
Buku Referensi
Thomas, Hugh, author
Harper & Brothers, 1961
Buku Teks
Mottram, Ralph Hale
Arrow Books, 1968
Buku Teks
compiled by Carlos Castillo & Otto F. Bond
The University of Chicago Press, 1948
Buku Referensi
Lea, Christine
New York: Oxford University Press, 1993,
Buku Referensi