diff --git a/kadmos/graph/mixin_vistoms.py b/kadmos/graph/mixin_vistoms.py
index eed85d42b525b6aaf9f92a1b97dcea26b4a133fa..276bd53f67c6a0496d3a3785c689628f602a32a2 100644
--- a/kadmos/graph/mixin_vistoms.py
+++ b/kadmos/graph/mixin_vistoms.py
@@ -45,7 +45,6 @@ LOCAL_FILE_REFS = dict(REP__Acknowledgements__REP=os.path.join(LOCAL_PATH_PICTUR
                        REP__glyphicons_woff2__REP=os.path.join(LOCAL_PATH_PICTURES, "glyphicons-halflings-regular.woff2").replace('\\', '/'))
 
 
-
 class VistomsMixin(object):
 
     def vistoms_start(self, file_dir=None, mpg=None):
@@ -1153,7 +1152,7 @@ def get_vistoms_tree_viewer(xml_file, vistoms_dir, use_png_figs=False, file_refs
     else:
         rep = file_refs
         for key, item in LOCAL_FILE_REFS.iteritems():
-            assert key in rep, 'Replacement key %s is missing in the file_refs.' % key
+            assert key in rep or 'glyphicons' in key, 'Replacement key %s is missing in the file_refs.' % key
         rep['REP__GRAPH_DATA__REP'] = data_str
 
     # Perform the text replacement