cebe\markdown\inline\LinkTrait::identifyReference PHP Method

    protected function identifyReference($line)
    {
        return ($line[0] === ' ' || $line[0] === '[') && preg_match('/^ {0,3}\\[(.+?)\\]:\\s*([^\\s]+?)(?:\\s+[\'"](.+?)[\'"])?\\s*$/', $line);
    }