Katz, Bill, author
R.R. Bowker Company, 1986
Buku Referensi
Katz, Bill, author
R.R. Bowker, 1989
Buku Referensi
William Miller; Rita M. Pellen
The Hawort Information Press, 2005
Buku Teks
Rowley, Jennifer, author
Clive Bingley , 1980
Buku Teks
Varnum, Kenneth J., author
Learning Matters, 2012
Buku Teks