Reference library cyberlink

I reference the CyberLink library inside another target in an iPhone project. But I have some bugs while compiling when I implemented a CyberLink class. those kind of errors :

Undefined symbols:
  "_xmlParseDocument", referenced from:
      _cg_libxml2_parsewrapper in libCyberLink.a(cxml_parser_libxml2.o)
  "_xmlGetPredefinedEntity", referenced from:
      _cg_libxml2_get_entity in libCyberLink.a(cxml_parser_libxml2.o)
  "_xmlCreateMemoryParserCtxt", referenced from:
      _cg_libxml2_parsewrapper in libCyberLink.a(cxml_parser_libxml2.o)
  "_xmlFreeParserCtxt", referenced from:
      _开发者_如何学编程cg_libxml2_parsewrapper in libCyberLink.a(cxml_parser_libxml2.o)
  "_xmlFreeDoc", referenced from:
      _cg_libxml2_parsewrapper in libCyberLink.a(cxml_parser_libxml2.o)
ld: symbol(s) not found
collect2: ld returned 1 exit status

If somebody can help me, it would be nice =)

You have to add -lxml2 in the "other linker flags" properties of the build tab in the info of your target.