http://techonthenet.com/oracle
http://www.ss64.com/oraplsql/
http://www.orafaq.com/
http://www.csee.umbc.edu/help/oracle8/server.815/A67842/06_ERRS.HTM
http://www.dbaclick.com/forums/index.php?s=9a4559b30a7496d4bf96840ca2f0dda7
http://www.dbforums.com
