Nobes, C.W., author
Philip Allan/St. Martin Press, 1988
Buku Teks
Radebaugh, Lee H., author
John Wiley & Sons, 1993
Buku Teks
Riahi-Belkaoui, Ahmed, 1943-, author
Quorum Books, 1988
Buku Teks
United Nations, 1986
Buku Teks
Mueller, Gerhard G., author
Irwin, 1991
Buku Teks