Paton, Stewart, author
Routledge, 2008
Buku Referensi
Crystal, David, 1941-, author
Blackwell Publishers, 1998
Buku Referensi
Trask, R.L., author
Routledge, 1996
Buku Referensi
Crystal, David, 1941-, author
Westview Press, 1980
Buku Referensi
War Departement, 1944
Buku Referensi