Worthington, Ian, 1946-, author
Prentice-Hall, 2001
Buku Teks
Heidensohn, Klaus
John Wiley and Sons, 1975
Buku Teks
Townsend, Harry, author
Routledge , 1995
Buku Teks
Moss, Scott J.
Robertson, 1981
Buku Teks
Baye, Michael R., author
McGraw-Hill, 2003
Buku Teks