Dorian, A.F., author
Elsevier Scientific Publishing Company, 1981
Buku Referensi
Oxford University Press, New York
Buku Referensi
Gordon, Michael, author
Kogan Page, 1984
Buku Referensi
Peter Salim, author
Modern English Press, 1991
Buku Referensi
Gordon, Michael, author
Kogan Page, 1986
Buku Referensi