diff --git a/.gitignore b/.gitignore
index e097450..ca07a64 100644
--- a/.gitignore
+++ b/.gitignore
@@ -1 +1,2 @@
 docbook-5.0.zip
+/docbook-v5.1-os.zip
diff --git a/sources b/sources
index cc429bd..cbec63c 100644
--- a/sources
+++ b/sources
@@ -1 +1,2 @@
-2411c19ed4fb141f3fa3d389fae40736  docbook-5.0.zip
+SHA512 (docbook-5.0.zip) = a245796881762cf001f0d32b7c87315cba0454750d6b4178e4546357e320e2ab602d84c08a7e44329f406a8d32340605671c351e87c0b9097582ebf6d10fede4
+SHA512 (docbook-v5.1-os.zip) = b55f8eda4dcff9d4ebd31876bc33c244ef3884afc167da1425531266963ba64000fbe619ec7c049ae65c0aab864a5a7228caef08b53f546e2686296d97190873