Hylton, Keith N, Author
Cambridge University Press, 2003
eBooks
edited by Douglas E. Edlin
Cambridge University Press, 2007
Buku Teks
Sheth, Jagdish N., author
John Wiley & Sons, 1988
Buku Teks
Gellhorn, Ernest, author
West , 1994
Buku Teks
Gellhorn, Ernest, author
St.paul Minn, 1986
Buku Teks