Ellis, Rodney A., author
Thomson, 2003
Buku Teks
Glueck, William F., author
McGraw-Hill, 1972
Buku Teks
Glueck, William F., author
McGraw-Hill, 1976
Buku Teks
Hall, Chris
Pacific Economic Cooperation Council, 1995
Buku Teks
Mosely, Philip E.
Vintage Books, 1960
Buku Teks