diff -r 29bb1ebb188f -r efd995488228 src/LCF/ROOT
--- a/src/LCF/ROOT	Sun Sep 08 13:07:03 2019 +0200
+++ b/src/LCF/ROOT	Sun Sep 08 16:49:05 2019 +0200
@@ -10,6 +10,7 @@
     Useful references on LCF: Lawrence C. Paulson,
     Logic and Computation: Interactive proof with Cambridge LCF (CUP, 1987)
   "
+  directories "ex"
   sessions
     FOL
   theories