Add link to Airbus Defence and Space presentation

index.html

@@ -54,9 +54,11 @@ layout: home_orekit
     <ul class="fa-ul">
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         <p><a href="https://www.airbus.com/space.html">Airbus Defence and Space</a>
-          (ADS) uses Orekit in Quartz, it's new generation flight dynamics
-          software. In addition, ADS actively contributes to Orekit and is
-          member of its Project Management Committee (PMC).</p>
+          (ADS) uses Orekit in
+          <a href="https://orekit.org/doc/orekit-day/2019/3%20-%20Quartz%20FDS%20presentation%20for%20Orekit%20Day%20-%20Airbus%20DS.pdf">Quartz</a>,
+          it's new generation flight dynamics software. In addition, ADS
+          actively contributes to Orekit and is member of its Project
+          Management Committee (PMC).</p>
       </li>
 
       <li><span class="fa-li fa-lg fa fa-gears"></span>