diff --git a/doc/Makefile.am b/doc/Makefile.am
index aee2d7b..15f36b7 100644
--- a/doc/Makefile.am
+++ b/doc/Makefile.am
@@ -1 +1,4 @@
-SUBDIRS = examples
+SUBDIRS = \
+	examples \
+	manuals \
+	$(NULL)