public function &GetMaxVat()
    {
        $iPointer = $this->getItemPointer();
        $oMaxVatItem = null;
        $this->GoToStart();
        while ($oItem = &$this->Next()) {
            $oCurrentVat = $oItem->GetVat();
            if (!is_null($oCurrentVat)) {
                if (is_null($oMaxVatItem)) {
                    $oMaxVatItem = $oCurrentVat;
                } elseif ($oMaxVatItem->fieldVatPercent < $oCurrentVat->fieldVatPercent) {
                    $oMaxVatItem = $oCurrentVat;
                }
            }
        }
        $this->setItemPointer($iPointer);

        return $oMaxVatItem;
    }