if (this.getBibliographicReferences() == null) { return result; }
    public List<BibliographicReference> getSecondaryBibliographicReferences() throws FenixFilterException, FenixServiceException {        final List<BibliographicReference> result = new ArrayList<BibliographicReference>();        for (final BibliographicReference bibliographicReference : getBibliographicReferences()) {            if (bibliographicReference.getType().equals(BibliographicReferenceType.SECONDARY)) {                result.add(bibliographicReference);            }        }        return result;    }