public void WriteNamespace (NamespaceReference spaceReference, DisplayOptions options, XmlWriter writer) {
            if (spaceReference == null) throw new ArgumentNullException("spaceReference");
            if (writer == null) throw new ArgumentNullException("writer");

            NamespaceTarget spaceTarget = spaceReference.Resolve(targets) as NamespaceTarget;
            if (spaceTarget != null) {
                WriteNamespaceTarget(spaceTarget, options, writer);
            } else {
                TextReferenceUtilities.WriteNamespaceReference(spaceReference, options, writer);
            }
        }