Chess openings

http://chessopenings.com/
http://www.chessopolis.com/openings.htm
http://chess.about.com/od/openings/tp/TopOpenings.htm
http://www.thechesswebsite.com/chess-openings/index.php
http://chessopenings.org/
http://chess-openings-for-beginners.blogspot.com/
http://www.chesscentral.com/Chess_Strategy_a/201.htm
http://en.wikibooks.org/wiki/Chess_Opening_Theory
http://www.365chess.com/opening.php
http://www.amazon.com/Ideas-Behind-Chess-Openings-Algebraic/dp/0812917561
http://www.chess.com/openings/
http://chessbase-shop.com/es/products/the_abc_of_chess_openings-2nd_edition
http://www.learn-chess.com/chess_openings/
http://www.dummies.com/how-to/content/understanding-the-basics-of-chess-openings.html