Empty href attributes in OpenURL links

OpenURL links are created with empty href attributes: seems to be a missing not-flag in biblio_theme.inc:biblio_openURL. Changing:

if (empty($openURLResolver)) {
    $co = biblio_contextObject($node);
    ...

to

  if (!empty($openURLResolver)) {
    $co = biblio_contextObject($node);

... corrects the problem.