Add reference to icons

Author: fabian

index.html

@@ -46,6 +46,10 @@ <h1>Code Driven Infrastructure and&nbsp;Deployment</h1>
 This document has been written in HTML and was converted into a PDF document with <a href="#ref-prince">Prince</a>. The font used is <em>Helvetica Neue</em>, created by D.&nbsp;Stempel&nbsp;AG and based on <em>Helvetica</em> by Max Miedinger.
 </p>
 
+<p>
+The icons used on the cover and in this document are from <a href="#ref-small-n-flat">small-n-flat</a>, they are released to the public domain.
+</p>
+
 </div>
 
 
@@ -5621,6 +5625,12 @@ <h3>Bibliography</h3>
     (retrieved&nbsp;21.&nbsp;April&nbsp;2015)
 </p>
 
+<p id="ref-small-n-flat" class="reference-item">
+    <span class="ref">Chesne A. (2014): small-n-flat</span>.
+    <a href="http://paomedia.github.io/small-n-flat/" target="_blank">http://paomedia.github.io/small-n-flat/</a>
+    (retrieved&nbsp;3.&nbsp;November&nbsp;2015)
+</p>
+
 <p id="ref-codeship" class="reference-item">
     <span class="ref">Codeship (2015): Codeship</span>.
     <a href="https://codeship.com/" target="_blank">https://codeship.com/</a>