diff -r bef14fa789ef -r 98b6cd12f963 src/Pure/Thy/sessions.scala
--- a/src/Pure/Thy/sessions.scala	Thu Dec 28 14:20:48 2017 +0100
+++ b/src/Pure/Thy/sessions.scala	Thu Dec 28 21:45:28 2017 +0100
@@ -30,7 +30,7 @@
   def exclude_session(name: String): Boolean = name == "" || name == DRAFT
 
   def exclude_theory(name: String): Boolean =
-    name == root_name || name == "README" || name == "index"
+    name == root_name || name == "README" || name == "index" || name == "bib"
 
 
   /* base info and source dependencies */