John Wiley & Sons, 1983
Buku Teks
Walker, Terry M., author
Allyn and Bacon, 1972
Buku Teks
Haenssgen, Marco J., author
Emerald Publishing Limited, 2019
eBooks
Thompson, James D., author
Transaction Publishers, 2003
Buku Teks
Brown, Brian, author
Open University Press, 2003
Buku Teks