docs: Updating documentation for ndnSIM 2.5 release

Change-Id: Ia1dba06a9afd66a810171d4a512f35f6df6ba22a
diff --git a/docs/source/_templates/indexcontent.html b/docs/source/_templates/indexcontent.html
index f7134ce..7d73e6e 100644
--- a/docs/source/_templates/indexcontent.html
+++ b/docs/source/_templates/indexcontent.html
@@ -76,16 +76,26 @@
           <p class="biglink"><a class="biglink" href="{{ pathto("ndnsim-research-papers") }}">ndnSIM-related publications</a><br/>
             <span class="linkdescr">general papers about ndnSIM, research papers that use ndnSIM</span></p>
           <p>If you are referring to ndnSIM in a published work, please cite the following papers, not just the ndnSIM website. Thank you!
-          <ul>
+          <ul style="padding-left:20px">
             <li>
-              S. Mastorakis, A. Afanasyev, and L. Zhang, "On the Evolution of ndnSIM: an Open-Source Simulator for NDN Experimentation," ACM SIGCOMM Computer Communication Review (CCR), July 2017 (<a class="reference external" href="https://ccronline.sigcomm.org/wp-content/uploads/2017/08/sigcomm-ccr-final112-full-letter.pdf">PDF</a>) (<a class="reference external" href="http://web.cs.ucla.edu/~mastorakis/bibtex-ndnsim">BibTex</a>)
+              <b>For ndnSIM >= 2.0:</b>
             </li>
+              <ul style="padding-left:30px">
+                <li>
+                S. Mastorakis, A. Afanasyev, and L. Zhang, "On the Evolution of ndnSIM: an Open-Source Simulator for NDN Experimentation," ACM SIGCOMM Computer Communication Review (CCR), July 2017 (<a class="reference external" href="https://ccronline.sigcomm.org/wp-content/uploads/2017/08/sigcomm-ccr-final112-full-letter.pdf">PDF</a>) (<a class="reference external" href="http://web.cs.ucla.edu/~mastorakis/bibtex-ndnsim">BibTex</a>)
+                </li>
+                <li>
+                S. Mastorakis, A. Afanasyev, I. Moiseenko, and L. Zhang, &#8220;ndnSIM 2: An updated NDN simulator for NS-3,&#8221; NDN, Technical Report NDN-0028, Revision 2, 2016 (<a class="reference external" href="https://named-data.net/wp-content/uploads/2016/11/ndn-0028-2-ndnsim-v2.pdf">PDF</a>) (<a class="reference external" href="http://lasr.cs.ucla.edu/afanasyev/bibwiki/bibtex/399">BibTex</a>)
+                </li>
+              </ul>
             <li>
-              S. Mastorakis, A. Afanasyev, I. Moiseenko, and L. Zhang, &#8220;ndnSIM 2: An updated NDN simulator for NS-3,&#8221; NDN, Technical Report NDN-0028, Revision 2, 2016 (<a class="reference external" href="https://named-data.net/wp-content/uploads/2016/11/ndn-0028-2-ndnsim-v2.pdf">PDF</a>) (<a class="reference external" href="http://lasr.cs.ucla.edu/afanasyev/bibwiki/bibtex/399">BibTex</a>)
+              <b> For ndnSIM 1.0:</b>
             </li>
-            <li>
-            A. Afanasyev, I. Moiseenko, and L. Zhang, &#8220;ndnSIM: NDN simulator for NS-3,&#8221; NDN, Technical Report NDN-0005, 2012 (<a class="reference external" href="https://named-data.net/wp-content/uploads/TRndnsim.pdf">PDF</a>) (<a class="reference external" href="http://lasr.cs.ucla.edu/afanasyev/bibwiki/bibtex/367">BibTex</a>)
-            </li>
+              <ul style="padding-left:30px">
+                <li>
+                A. Afanasyev, I. Moiseenko, and L. Zhang, &#8220;ndnSIM: NDN simulator for NS-3,&#8221; NDN, Technical Report NDN-0005, 2012 (<a class="reference external" href="https://named-data.net/wp-content/uploads/TRndnsim.pdf">PDF</a>) (<a class="reference external" href="http://lasr.cs.ucla.edu/afanasyev/bibwiki/bibtex/367">BibTex</a>)
+                </li>
+              </ul>
           </ul>
         </div>
       </td>