[information-technology] add “sources”

revealjs/information-technology/2-products.md

@@ -16,9 +16,7 @@ background-image="img/jannik/windows.jpg"
 ## Windows
 
 <notes>
- * essential software on your computer that it needs to work Hardware
- * needed to use all the software and services and to access the internet to
-   communicate
+ * essential software on your computer that it needs to work
 </notes>
 
 ---
@@ -60,3 +58,8 @@ background-image="img/jannik/cc.svg"
 background-image="img/jannik/hardware.jpg"
 
 ## Hardware
+
+<notes>
+ * needed to use all the software and services and to access the internet to
+   communicate
+</notes>

revealjs/information-technology/4-end.md

@@ -21,6 +21,8 @@ style="font-size: 24px;"
 
 <hr/>
 
+ * [Adobe: Creative Cloud](https://www.adobe.com/de/creativecloud.html)
+ * [Microsoft: Windoows](https://www.microsoft.com/de-de/windows)
  * Unsplash:
    [Jakob Owens](https://unsplash.com/photos/CiUR8zISX60),
    [Facycrave](https://unsplash.com/photos/58tOB36ZTnw),