function createSerialVersionNode($doc, $issn, $productForm, $epubFormat = null)
{
$deployment = $this->getDeployment();
$context = $deployment->getContext();
$serialVersionNode = $doc->createElementNS($deployment->getNamespace(), 'SerialVersion');
// Proprietary Journal Identifier
if ($productForm == O4DOI_PRODUCT_FORM_ELECTRONIC) {
$serialVersionNode->appendChild($this->createIdentifierNode($doc, 'Product', O4DOI_ID_TYPE_PROPRIETARY, $context->getId()));
}
// ISSN
if (!empty($issn)) {
$issn = PKPString::regexp_replace('/[^0-9]/', '', $issn);
$serialVersionNode->appendChild($this->createIdentifierNode($doc, 'Product', O4DOI_ID_TYPE_ISSN, $issn));
}
// Product Form
$serialVersionNode->appendChild($node = $doc->createElementNS($deployment->getNamespace(), 'ProductForm', $productForm));
if ($productForm == O4DOI_PRODUCT_FORM_ELECTRONIC) {
// ePublication Format
if ($epubFormat) {
$serialVersionNode->appendChild($node = $doc->createElementNS($deployment->getNamespace(), 'EpubFormat', $epubFormat));
}
// ePublication Format Description
$serialVersionNode->appendChild($node = $doc->createElementNS($deployment->getNamespace(), 'EpubFormatDescription', 'Open Journal Systems (OJS)'));
}
return $serialVersionNode;
}