Elliott, John P., author
Kluwer Academic, 1999
Buku Teks
Hart, Andrew, author
Routledge, 1997
Buku Referensi
Thorn, Eric A., author
Jay Books, 1989
Buku Referensi
Hogan, Rex, 1944-, author
Prentice-Hall, 1990
Buku Teks
Church, James C., author
McGraw-Hill, 1979
Buku Referensi