static {
   tagMap.put("DC.Format", MetadataField.FIELD_FORMAT);
   tagMap.put("DC.Language", MetadataField.FIELD_LANGUAGE);
   tagMap.put("citation_publisher", MetadataField.FIELD_PUBLISHER);
   tagMap.put("citation_journal_title", MetadataField.FIELD_PUBLICATION_TITLE);
   tagMap.put("citation_title", MetadataField.FIELD_ARTICLE_TITLE);
   tagMap.put("citation_date", MetadataField.FIELD_DATE);
   tagMap.put("citation_publication_date", MetadataField.FIELD_DATE);
   tagMap.put(
       "citation_authors",
       new MetadataField(MetadataField.FIELD_AUTHOR, MetadataField.splitAt(";")));
   tagMap.put("citation_author", MetadataField.FIELD_AUTHOR);
   tagMap.put("citation_issn", MetadataField.FIELD_ISSN);
   tagMap.put("citation_volume", MetadataField.FIELD_VOLUME);
   tagMap.put("citation_issue", MetadataField.FIELD_ISSUE);
   tagMap.put("citation_firstpage", MetadataField.FIELD_START_PAGE);
   tagMap.put("citation_lastpage", MetadataField.FIELD_END_PAGE);
   tagMap.put("citation_doi", MetadataField.FIELD_DOI);
   tagMap.put("citation_public_url", MetadataField.FIELD_ACCESS_URL);
   // typical field value: "acupmed;30/1/8": extract "acupmed"
   tagMap.put(
       "citation_mjid",
       new MetadataField(
           MetadataField.FIELD_PROPRIETARY_IDENTIFIER, MetadataField.extract("^([^;]+);", 1)));
 }