use XML::DOM;
my $parser = new XML::DOM::Parser(ErrorContext => 1);
$text='put any xml text here';
my $doc;
if (! defined(eval {$doc = $parser->parse($text)})) {
  my $errs = $@;
  die("Did not parse: $errs\n");
}
$doc->normalize();
print $doc->toString;

##</code><code>##

</ref><see-also seeref="Prothrow&ndash;Stith">

##</code><code>##

</ref>&ndash;<see-also seeref="ProthrowStith">