spec: move reference implementation to the end
diff --git a/docs/imsi-pseudo-spec.adoc b/docs/imsi-pseudo-spec.adoc
index 90fec9b..17e4476 100644
--- a/docs/imsi-pseudo-spec.adoc
+++ b/docs/imsi-pseudo-spec.adoc
@@ -379,20 +379,6 @@
 // === SMS Arrives Before Timer Expires
 // FIXME: OS#4486
 
-[[reference-src]]
-== Reference Implementation with Source Code
-
-A reference implementation for the SIM applet (<<sim-app>>) is available in
-source code under the Apache-2.0 license at:
-
-https://osmocom.org/projects/imsi-pseudo
-
-The HLR modifications described in <<hlr-imsi-pseudo-storage>> and
-<<process-update-location-hlr>> were implemented for reference in OsmoHLR from
-the Osmocom project, licensed under AGPL-3.0. Information about the source code
-and related branches for IMSI pseudonymization can be found at the above URL as
-well.
-
 == Recommendations for Real-World Implementations
 
 === BCCH SI3: ATT = 0
@@ -438,5 +424,19 @@
 * A Samsung GT-E1200 feature phone displays a waiting screen for 16 to 17
   seconds and is unusable during that time.
 
+[[reference-src]]
+== Reference Implementation with Source Code
+
+A reference implementation for the SIM applet (<<sim-app>>) is available in
+source code under the Apache-2.0 license at:
+
+https://osmocom.org/projects/imsi-pseudo
+
+The HLR modifications described in <<hlr-imsi-pseudo-storage>> and
+<<process-update-location-hlr>> were implemented for reference in OsmoHLR from
+the Osmocom project, licensed under AGPL-3.0. Information about the source code
+and related branches for IMSI pseudonymization can be found at the above URL as
+well.
+
 <<<
 include::./common/chapters/gfdl.adoc[]