Encyclopedia of Australia
Andrew, Nancy Learmonth, compiled
Frederick Warne & Co , 1973
 Buku Referensi
Crystal, David, 1941-
The Cambridge encyclopedia of language
Cambridge University Press, 1991
 Buku Referensi
Cambridge encyclopedia of China
New York Cambridge University Press 1991
 Buku Referensi
Crystal, David, 1941-
The Cambridge encyclopedia of language
Cambridge University Press, 1997
 Buku Referensi
Crystal, David, 1941-
The Cambridge encyclopedia of language
Cambridge University Press, 1994
 Buku Referensi