D-Net

                r.setExternalReference(convertExternalRefs(oaf));

    private static List<ExternalReference> convertExternalRefs(OafProtos.Oaf oaf) {

        ResultProtos.Result r = oaf.getEntity().getResult();

        if (r.getExternalReferenceCount() > 0) {

            return r.getExternalReferenceList()

                    .stream()

                    .map(e -> convertExtRef(e))

                    .collect(Collectors.toList());

        }

        return Lists.newArrayList();

    }

    private static ExternalReference convertExtRef(ResultProtos.Result.ExternalReference e) {

        ExternalReference ex = new ExternalReference();

        ex.setUrl(e.getUrl());

        ex.setSitename(e.getSitename());

        ex.setRefidentifier(e.getRefidentifier());

        ex.setQuery(e.getQuery());

        ex.setQualifier(mapQualifier(e.getQualifier()));

        ex.setLabel(e.getLabel());

        ex.setDescription(e.getDescription());

        ex.setDataInfo(ex.getDataInfo());

        return ex;

    }