$re = '/(<Reference Include=")(DevExpress\.\D+\.v14\.1)(, Version=14\.1\.10\.0, Culture=neutral, PublicKeyToken=\S+, processorArchitecture=MSIL">)[\r\n\s]*(<SpecificVersion>False<\/SpecificVersion>)[\r\n\s]*(<\/Reference>)/';
$str = ' <Reference Include="DevExpress.Data.v14.1, Version=14.1.10.0, Culture=neutral, PublicKeyToken=b88d1754d700e49a, processorArchitecture=MSIL">
<SpecificVersion>False</SpecificVersion>
</Reference>';
preg_match($re, $str, $matches, PREG_OFFSET_CAPTURE, 0);
// Print the entire match result
var_dump($matches);
Please keep in mind that these code samples are automatically generated and are not guaranteed to work. If you find any syntax errors, feel free to submit a bug report. For a full regex reference for PHP, please visit: http://php.net/manual/en/ref.pcre.php