docs: Updating documentation for ndnSIM 2.5 release

Change-Id: Ia1dba06a9afd66a810171d4a512f35f6df6ba22a
diff --git a/docs/source/ndnsim-research-papers.rst b/docs/source/ndnsim-research-papers.rst
index 6644e79..4627132 100644
--- a/docs/source/ndnsim-research-papers.rst
+++ b/docs/source/ndnsim-research-papers.rst
@@ -7,7 +7,22 @@
 ---------------------------
 
 .. note::
-    if you refer to ndnSIM in a published work, please cite the following papers, not just the ndnSIM website
+    if you refer to ndnSIM in a published work, please cite the following papers, not just the ndnSIM website.
+
+**For ndnSIM >= 2.0:**
+
+- **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**  (`PDF <https://ccronline.sigcomm.org/wp-content/uploads/2017/08/sigcomm-ccr-final112-full-letter.pdf>`__, `BibTex <http://web.cs.ucla.edu/~mastorakis/bibtex-ndnsim>`__)
+
+    As a proposed Internet architecture, Named Data Networking (NDN) takes a
+    fundamental departure from today's TCP/IP architecture, thus requiring extensive
+    experimentation and evaluation. To facilitate such experimentation, we have developed
+    ndnSIM, an open-source NDN simulator based on the NS-3 simulation framework. Since its
+    first release in 2012, ndnSIM has gone through five years of active development and
+    integration with the NDN prototype implementations, and has become a popular platform
+    used by hundreds of researchers around the world. This paper presents an overview of the
+    ndnSIM design, the ndnSIM development process, the design tradeoffs, and the reasons
+    behind the design decisions. We also share with the community a number of lessons we
+    have learned in the process.
 
 - **S. Mastorakis, A. Afanasyev, I. Moiseenko, and L. Zhang, "ndnSIM 2.0: A new version of the NDN simulator for NS-3," NDN, Technical Report NDN-0028, 2015** (`PDF <http://named-data.net/techreport/ndn-0028-1-ndnsim-v2.pdf>`__, `BibTex <http://lasr.cs.ucla.edu/afanasyev/bibwiki/bibtex/399>`__)
 
@@ -21,6 +36,8 @@
     the ndn-cxx library (NDN C++ library with eXperimental eXtensions) and the NDN Forwarding Daemon
     (NFD) to enable experiments with real code in a simulation environment.
 
+**For ndnSIM 1.0:**
+
 - **A. Afanasyev, I. Moiseenko, and L. Zhang, "ndnSIM: NDN simulator for NS-3," NDN, Technical Report NDN-0005, 2012** (`PDF <http://named-data.net/wp-content/uploads/TRndnsim.pdf>`__, `BibTex <http://lasr.cs.ucla.edu/afanasyev/bibwiki/bibtex/367>`__)
 
     Named Data Networking (NDN) is a newly proposed Internet architecture.  NDN retains the