Hartley, Keith
John Wiley & Sons, c.1981
Buku Teks
Salvatore, Dominick, author
McGraw-Hill, 1983
Buku Teks
Salvatore, Dominick, author
McGraw-Hill, 1992
Buku Teks
Boulding, Kenneth E. (Kenneth Ewart), 1910-1993, author
Harper & Row, 1966
Buku Teks
Jehle, Geoffrey A., author
Prentice-Hall, 1991
Buku Teks