Vox, author
McGraw-Hill, 2012
Buku Referensi
compiled by Carlos Castillo & Otto F. Bond
The University of Chicago Press, 1948
Buku Referensi
McGraw-Hill, 2001
Buku Teks
Cuyas, Arturo, author
Appleton-Century-Crofts, 1962
Buku Referensi
Vollnhals, Otto, author
Routledge, 1992
Buku Referensi