Clark, John, author
Blackwell, 1995
Buku Teks
Bridgeman, Loraine I
New York International Journal of American Linguistics 1961
Buku Teks
Trask, R.L., author
Routledge, 1996
Buku Referensi
Odden, David
Cambridge Press, 2007
Buku Teks
Martinus Nijhoff, 1980
Buku Teks