Crystal, David, 1941-
The Cambridge encyclopedia of language
Cambridge University Press, 1994
 Buku Referensi
Crystal, David, 1941-
The Cambridge encyclopedia of the English language
Cambridge University Press, 1995
 Buku Referensi
Crystal, David, 1941-
The Cambridge encyclopedia of language
Cambridge University Press, 1991
 Buku Referensi
Crystal, David, 1941-
The Cambridge encyclopedia of language
Cambridge University Press, 1997
 Buku Referensi
The Cambridge encyclopedia of life sciences
edited by Adrian Friday, David S. Ingram
Cambridge University Press, 1985
 Buku Referensi