code: @Override
      public Collection<PersonDocument> findByFileAndSurnameBeginsWith(
              final String filename, final String beginsWith) {
          if (filename == null) {
              return Collections.emptyList();
          }
          final List<PersonDocumentMongo> personDocuments;
          if (beginsWith == null || beginsWith.equals("")
                  || beginsWith.equals("?")) {
              personDocuments = queryUnknownSurname(filename);
          } else {
              personDocuments = querySurnameBeginsWith(filename, beginsWith);
          }
          createGedObjects(personDocuments);
          return copy(personDocuments);
      }
docs: {@inheritDoc}