Dwyer, Denis John, author
Longman, 1979
Buku Teks
edited by Hamish Main and Stephen Why Williams
[Publisher not identified], 1994
Buku Teks
edited by Hamish Main and Stephen Wyn Williams
J. Wiley, 1994
Buku Teks
Payne, Geoffrey K., author
Leonard-Hill, 1977
Buku Teks
Meyerson, Martin, author
McGraw-Hill , 1962
Buku Teks