IN that case you can do something like:

use XML::DOM;
                                                                      
+              
                                                                      
+              
my $xml = 'jj.xml';
my $parser = new XML::DOM::Parser;
my $doc = $parser->parsefile($xml);
                                                                      
+              
my $nodes = $doc->getElementsByTagName ("ISSN");
                                                                      
+              
foreach my $node (@{$nodes})
{
   if ( $node->getFirstChild()->toString() eq '1742-7061' )
   {
      my $parent = $node->getParentNode();
      $doc->getFirstChild()->removeChild($parent);
   }
                                                                      
+              
}
                                                                      
+              
print $doc->toString();
[download]

Of course in your production code you will want to have all the ISSN numbers you want removed in a hash and do exists rather than the single comparison I have there.

/J\