-        if 'material' in element.attrib:
-            formats = re.split(r"[, ]+", element.attrib['format'])
+        if 'url' in element.attrib:
+            return tag('a', href=element.attrib['url'])(self, element)
+        elif 'material' in element.attrib:
+            formats = re.split(r"[, ]+",
+                               element.attrib.get('format', DEFAULT_MATERIAL_FORMAT))
+            make_url = lambda f: self.options['urlmapper'] \
+              .url_for_material(element.attrib['material'], f)
+            def_href = make_url(formats[0])