diff --git a/acknowledging.html b/acknowledging.html
index f5978d8..888ee5c 100644
--- a/acknowledging.html
+++ b/acknowledging.html
@@ -203,19 +203,16 @@ <h2 id="publication"><a href="#pub">In publications</a></h2>
 
         </ul>
 
-
-
 <!--
-        <br>
+        <br><br>
         <p>
              We provide the following LaTeX/BibTeX acknowledgment if there is no specific place to cite the papers:
             <center>
                 This research made use of gammapy,\footnote{https://www.gammapy.org} a community-developed core Python
-        package for TeV gamma-ray astronomy \citep{gammapy:2017}
+        package for TeV gamma-ray astronomy \citep{gammapy:2023}
             </center>
         </p>
 -->
-
         <br>
         <hr>
         <h2 id="presentation"><a href="#pres">In presentations</a></h2>