PhpOffice\PhpPresentation\Writer\PowerPoint2007\PptCharts::writeSingleValueOrReference PHP Method

    protected function writeSingleValueOrReference($objWriter, $isReference, $value, $reference)
    {
        if (!$isReference) {
            // Value
            $objWriter->writeElement('c:v', $value);
            return;
        }
        // Reference and cache
        $objWriter->startElement('c:strRef');
        $objWriter->writeElement('c:f', $reference);
        $objWriter->startElement('c:strCache');
        $objWriter->startElement('c:ptCount');
        $objWriter->writeAttribute('val', '1');
        $objWriter->endElement();
        $objWriter->startElement('c:pt');
        $objWriter->writeAttribute('idx', '0');
        $objWriter->writeElement('c:v', $value);
        $objWriter->endElement();
        $objWriter->endElement();
        $objWriter->endElement();
    }