$re = '/([A-Z][\w\-]+ )?\((\D*\d{4}(: ?[\d\-]*)*(, \d{4}(: ?[\d\-]*)*)*;?)*\)/';
$str = 'Graham (Doe 2016:45, 2012; Graham 2012, 2014:676-678; Smith 2008) writes that ...';
preg_match($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