protected function extractMetaData(ZipArchive $package)
    {
        // Data holders
        $coreProperties = array();

        // Read relations and search for core properties
        $relations = simplexml_load_string($package->getFromName("_rels/.rels"));
        foreach ($relations->Relationship as $rel) {
            if ($rel["Type"] == Zend_Search_Lucene_Document_OpenXml::SCHEMA_COREPROPERTIES) {
                // Found core properties! Read in contents...
                $contents = simplexml_load_string(
                    $package->getFromName(dirname($rel["Target"]) . "/" . basename($rel["Target"]))
                );

                foreach ($contents->children(Zend_Search_Lucene_Document_OpenXml::SCHEMA_DUBLINCORE) as $child) {
                    $coreProperties[$child->getName()] = (string)$child;
                }
                foreach ($contents->children(Zend_Search_Lucene_Document_OpenXml::SCHEMA_COREPROPERTIES) as $child) {
                    $coreProperties[$child->getName()] = (string)$child;
                }
                foreach ($contents->children(Zend_Search_Lucene_Document_OpenXml::SCHEMA_DUBLINCORETERMS) as $child) {
                    $coreProperties[$child->getName()] = (string)$child;
                }
            }
        }

        return $coreProperties;
    }