_:b21162173	<http://www.w3.org/1999/02/22-rdf-syntax-ns#type>	<mw:File> .
_:b21162173	<http://www.w3.org/2007/05/powder-s#describedby>	<http://dev.restore.ovi.cnr.it:8890/about/id/https/en.wikibooks.org/wiki/Chess_Opening_Theory> .