diff --git a/ontology/ontology.py b/ontology/ontology.py
index 1a3945a..616fa63 100644
--- a/ontology/ontology.py
+++ b/ontology/ontology.py
@@ -88,9 +88,9 @@ for string in sorted(strings):
             parent_items[parts[-2]], parts[-2]
         )
     if string in child_items:
-        parts_[-1] = '<a href="https://{}/clip/text/keywords=={}:_{}" target="_blank" title="{}">{}</a>'.format(
-            site, parts[-2].replace(' ', '_'), parts[-1].replace(' ', '_'),
-            child_items[string], parts[-1]
+        parts_[-1] = '<a href="https://{}/clip/text/keywords=={}{}" target="_blank" title="{}">{}</a>'.format(
+            site, '{}:_'.format(parts[-2].replace(' ', '_')) if parts[-2] != 'unknown' else '',
+            parts[-1].replace(' ', '_'), child_items[string], parts[-1]
         )
     html.append(': '.join(parts_))
 template = open('ontology_template.html').read()