diff --git a/.gitignore b/.gitignore
index 956bcf4..bc4bc90 100644
--- a/.gitignore
+++ b/.gitignore
@@ -4,3 +4,4 @@
 /Singular-3-1-7.tar.gz
 /singular-4.1.0p2.tar.gz
 /singular-4.1.0p3.tar.gz
+/surfex.tar.xz
diff --git a/Singular.spec b/Singular.spec
index 5ff547f..364b916 100644
--- a/Singular.spec
+++ b/Singular.spec
@@ -26,6 +26,7 @@ License:	GPLv2 or GPLv3
 Source0:	http://www.mathematik.uni-kl.de/ftp/pub/Math/Singular/SOURCES/%{upstreamver}/singular-%{version}.tar.gz
 # Java sources omitted from the source tarball.  To recreate this:
 # - git clone https://github.com/Singular/Sources.git
+# - cd Sources
 # - git checkout spielwiese
 # - git reset --hard df043ed9af2cfd53d92c247ae0d69fb0e74df729
 # - tar cJf surfex.tar.xz Singular/LIB/surfex
diff --git a/sources b/sources
index 7f62c16..79cce8d 100644
--- a/sources
+++ b/sources
@@ -1 +1,2 @@
 SHA512 (singular-4.1.0p3.tar.gz) = 9bf28e6f8a35d43840935496aacfce26aae8bc7a515d934195749a348e0230ff3021f0a853496bcc14f0cd934ac44e77f404fe44a56bc5b809d92a177ccb8d7f
+SHA512 (surfex.tar.xz) = 3b92245a5a5dde8fbb8b9ae638e7994231f158a61c9efb9633c57d458ec7e0cf196fed3292eb1b0f85fe67077a406dfc2523eb90d180046a5d9953876e8a5f85