Headquarters USA
Omnigraphics, 2003
 Buku Teks
Malmstrom, Jean
Dialects USA
National Council of Teachers of English, 1963
 Buku Teks SO
Malmstrom, Jean
Dialects USA
National Council of Teachers of English , 1963
 Buku Teks SO
InfoUSA : information USA
US. Department of State, 2005
 Multimedia
Dixson, Robert J.
The U.S.A.- : the land and the people
Regents Publishing, 1959
 Buku Teks SO