public function getMinDPrice()
    {
        $dMinPrice = $this->getDPrice();
        $aVariants = $this->getMdSubvariants();
        foreach ($aVariants as $oVariant) {
            $dMinVariantPrice = $oVariant->getMinDPrice();
            if (is_null($dMinPrice)) {
                $dMinPrice = $dMinVariantPrice;
            }
            if (!is_null($dMinVariantPrice) && $dMinVariantPrice < $dMinPrice) {
                $dMinPrice = $dMinVariantPrice;
            }
        }

        return $dMinPrice;
    }