Crystal, David, 1941-
Language death
Cambridge University Press, 2004
 Buku Teks
Crystal, David, 1941-
Language death
Cambridge University Press, 2005
 Buku Teks
Dalby, Andrew
Language in danger
A. Lane, 2002
 Buku Teks
Austin, Peter K., editor
The Cambridge handbook of endangered languages
Cambridge University Press, 2011
 eBooks
Harris, David P.
Testing english as a second language / David P. Harris
McGraw-Hill, 1969
 Buku Teks