Good Articles on oracle database novalidate clause, deferrable, various joins etc.

Below are the links for "novalidate" clause:
http://askanantha.blogspot.in/2007/09/difference-between-unique-index-and.html
http://richardfoote.wordpress.com/2008/07/28/novalidate-constraints-no-really/

For "deferrable initially deferred" clause:
http://infolab.stanford.edu/~ullman/fcdb/oracle/or-triggers.html
http://myorastuff.blogspot.in/2009/05/deferred-constraints.html

For various joins and examples on them:
http://dwhlaureate.blogspot.in/2012/08/joins-in-oracle.html

For various index types and creation of indexes:
http://dwhlaureate.blogspot.in/2012/08/what-is-index-and-its-usehow-to-create.html