protected function _listeArab2Rom($nbArabic)
    {
        $nbBaseTen  = array('I','X','C','M');
        $nbBaseFive = array('V','L','D');
        $nbRoman    = '';

        if ($nbArabic<1) {
            return $nbArabic;
        }
        if ($nbArabic>3999) {
            return $nbArabic;
        }

        for ($i=3; $i>=0; $i--) {
            $digit=floor($nbArabic/pow(10, $i));
            if ($digit>=1) {
                $nbArabic -= $digit*pow(10, $i);
                if ($digit<=3) {
                    for ($j=$digit; $j>=1; $j--) {
                        $nbRoman .= $nbBaseTen[$i];
                    }
                } elseif ($digit == 9) {
                    $nbRoman .= $nbBaseTen[$i].$nbBaseTen[$i+1];
                } elseif ($digit == 4) {
                    $nbRoman .= $nbBaseTen[$i].$nbBaseFive[$i];
                } else {
                    $nbRoman .= $nbBaseFive[$i];
                    for ($j=$digit-5; $j>=1; $j--) {
                        $nbRoman .= $nbBaseTen[$i];
                    }
                }
            }
        }
        return $nbRoman;
    }