diff --git a/ROOT b/ROOT
index f5af040..7254537 100644
--- a/ROOT
+++ b/ROOT
@@ -1,5 +1,7 @@
 session "Isabelle_DOF" = "Functional-Automata" + 
   options [document = pdf, document_output = "output"]
+  sessions
+    "Regular-Sets"
   theories
     Isa_DOF
     "ontologies/CENELEC_50126"