private void writeModel(Model model, RDFFormat format, OutputStream out) throws RDFHandlerException {
final RDFHandler writer = new BufferedGroupingRDFHandler(Rio.createWriter(format, out));
writer.startRDF();
writer.handleNamespace("rdf", RDF.NAMESPACE);
writer.handleNamespace("rdfs", RDFS.NAMESPACE);
writer.handleNamespace("skos", SKOS.NAMESPACE);
writer.handleNamespace("dc", DC.NAMESPACE);
writer.handleNamespace("primal", PRIMAL.NAMESPACE);
for (final Statement st : model) {