private function writeHyperlinks(XMLWriter $objWriter, PhpspreadsheetWorksheet $pSheet)
    {
        // Hyperlink collection
        $hyperlinkCollection = $pSheet->getHyperlinkCollection();

        // Relation ID
        $relationId = 1;

        // Write hyperlinks?
        if (!empty($hyperlinkCollection)) {
            $objWriter->startElement('hyperlinks');

            foreach ($hyperlinkCollection as $coordinate => $hyperlink) {
                $objWriter->startElement('hyperlink');

                $objWriter->writeAttribute('ref', $coordinate);
                if (!$hyperlink->isInternal()) {
                    $objWriter->writeAttribute('r:id', 'rId_hyperlink_' . $relationId);
                    ++$relationId;
                } else {
                    $objWriter->writeAttribute('location', str_replace('sheet://', '', $hyperlink->getUrl()));
                }

                if ($hyperlink->getTooltip() != '') {
                    $objWriter->writeAttribute('tooltip', $hyperlink->getTooltip());
                }

                $objWriter->endElement();
            }

            $objWriter->endElement();
        }
    }