function array_duplicates(&$array)
{
    $keys = array_keys($array);
    $count = count($keys);
    $occurs = array();
    $result = array();
    
    for($i = 0; $i < $count; $i++)
    {
        $key =& $keys[$i];
        $value =& $array[$key];
        if(isset($occurs[$value]))
        {
            if($occurs[$value])
            {
                $result[$key] = $value;
                //$occurs[$value] = 2;
            }
        }
        else
        {
            $occurs[$value] = 1;
        }
    }
    return $result;
}