* Receives the value of the ODFDOM attribute representation <code>TextIssnAttribute</code> , See {@odf.attribute text:issn}
*
* @return - the <code>String</code> , the value or <code>null</code>, if the attribute is not set and no default value defined.
*/
public String getTextIssnAttribute() {
TextIssnAttribute attr = (TextIssnAttribute) getOdfAttribute(OdfDocumentNamespace.TEXT, "issn");
if (attr != null) {
return String.valueOf(attr.getValue());
}
return null;
}