edited by, Alan Williams
Emap , 1993
Buku Referensi
Willis, Claire, author
Pitman, 1992
Buku Teks
Brown, T. Merritt, author
Macmillan, 1970
Buku Teks
Sheppard, Deri, author
McGraw-Hill, 1995
Buku Teks
Leamer, Edward E., author
John Wiley & Sons, 1978
Buku Teks