diff --git a/.gitmodules b/.gitmodules
index e4a932a9e942873b02f16677487fe24e62e59f2d..6ce6a31bec517a9985964508bfb9387f82c7acc8 100644
--- a/.gitmodules
+++ b/.gitmodules
@@ -7,3 +7,6 @@
 [submodule "ulo/AFP"]
 	path = ulo/libraries/isabelle-afp
 	url = git@gl.mathhub.info:Isabelle/AFP.git
+[submodule "ulo/ulo"]
+	path = ulo/ulo-owl
+	url = git@gl.mathhub.info:ulo/ulo.git
diff --git a/ulo/ulo-owl b/ulo/ulo-owl
new file mode 160000
index 0000000000000000000000000000000000000000..47f9a8696b8579cfc46532d326da15aef1fb6134
--- /dev/null
+++ b/ulo/ulo-owl
@@ -0,0 +1 @@
+Subproject commit 47f9a8696b8579cfc46532d326da15aef1fb6134