diff --git a/Makefile.am b/Makefile.am
index 9832b58..ec76bff 100644
--- a/Makefile.am
+++ b/Makefile.am
@@ -1,6 +1,6 @@
 AUTOMAKE_OPTIONS = foreign dist-bzip2
 
-SUBDIRS = src include
+SUBDIRS = src include doc
 
 EXTRA_DIST = asn1 .version README.md