Add references

xep-xxxx-current-off-the-record-messaging-usage.md

@@ -3,21 +3,27 @@
 ## Introduction
 
 The Off-the-Record messaging protocol (OTR) was originally introduced in the
-2004 paper [Off-the-Record Communication, or, Why Not To Use PGP](https://otr.cypherpunks.ca/otr-wpes.pdf) [1]
+2004 paper 'Off-the-Record Communication, or, Why Not To Use PGP' [\[1\]](#references)
 and has since become an standard for performing end-to-end encryption. OTR
 provides confidentiality, deniability, authentication, forward secrecy and
 post-compromise security.
 
 The OTR protocol itself (in its latest version) is currently described by the
-document: Off-the-Record Messaging Protocol version 4 [2] and will not be
-described here. Instead, this document aims to describe OTR's usage in its
-current version (version 4) and best practices of using it within XMPP.
+document: Off-the-Record Messaging Protocol version 4 [\[2\]](#references) and
+will not be described in detail over here. Instead, this document aims to
+describe OTR's usage in its current version (version 4) and best practices of
+using it within XMPP.
 
 ## Overview
 
 Though this document will not focus on the OTR protocol itself, a brief overview
 is warranted to better understand the protocols strengths and weaknesses.
 
+OTR provides several cryptographic properties depending of what kind of
+conversation in established.
+
+confidentiality, deniability, authentication, forward secrecy and
+post-compromise security.
 OTR (in its version 4) uses several cryptographic algorithms, such as SHAKE-256
 and ChaCha20. An OTR session can be held only between two parties, meaning that
 OTR is incompatible with Multi-User Chat (XEP-0045) [3] and Mediated Information
@@ -42,3 +48,9 @@ Must contain:
 Additional:
 * Toolkit?
 
+
+## References
+
+1. Borisov, N., Goldberg, I. and Brewer, E. (20004). *Off-the-Record Communication,
+   or, Why Not To Use PGP*, WPES’04. Available at:
+   https://otr.cypherpunks.ca/otr-wpes.pdf