diff --git a/docs/page/timeplan/index.html b/docs/page/timeplan/index.html
index fbcd2ad..73d80d4 100644
--- a/docs/page/timeplan/index.html
+++ b/docs/page/timeplan/index.html
@@ -323,7 +323,7 @@ <h1>Timeplan</h1>
 <td align="right">13-..</td>
 <td>10a. Big Data Intro</td>
 <td align="center">DDL</td>
-<td align="center"><a href="https://github.com/abjer/sds/blob/master/material/session_10/lecture_10a.ppt">ppt</a>, <a href="https://github.com/abjer/sds/blob/master/material/session_10/lecture_10a.pdf">pdf</a></td>
+<td align="center"><a href="https://github.com/abjer/sds/blob/master/material/session_10/lecture_10a.pptx">pptx</a>, <a href="https://github.com/abjer/sds/blob/master/material/session_10/lecture_10a.pdf">pdf</a></td>
 <td></td>
 </tr>
 
@@ -332,7 +332,7 @@ <h1>Timeplan</h1>
 <td align="right">..-16</td>
 <td>10b. Ethics</td>
 <td align="center">DDL</td>
-<td align="center"><a href="https://github.com/abjer/sds/blob/master/material/session_10/lecture_10b.ppt">ppt</a>, <a href="https://github.com/abjer/sds/blob/master/material/session_10/lecture_10b.pdf">pdf</a></td>
+<td align="center"><a href="https://github.com/abjer/sds/blob/master/material/session_10/lecture_10b.pptx">pptx</a>, <a href="https://github.com/abjer/sds/blob/master/material/session_10/lecture_10b.pdf">pdf</a></td>
 <td></td>
 </tr>
 
@@ -505,7 +505,7 @@ <h4 id="legend">Legend</h4>
 <li>ex: Exercise ready to be made</li>
 <li>sol: Solution for exercise (Without solutions to the exercises you have to hand in)</li>
 <li>key: Slides in Apple Keynote format</li>
-<li>ppt: PowerPoint slides</li>
+<li>pptx: PowerPoint slides</li>
 </ul>
 
 
diff --git a/material/session_9/lecture_9.pdf b/material/session_9/lecture_9.pdf
new file mode 100644
index 0000000..f1645c2
Binary files /dev/null and b/material/session_9/lecture_9.pdf differ
diff --git a/src/content/page/timeplan.md b/src/content/page/timeplan.md
index 63b21ec..37db785 100755
--- a/src/content/page/timeplan.md
+++ b/src/content/page/timeplan.md
@@ -21,8 +21,8 @@ Aug 15| 13-16 | 6. Data structuring 2 | ABN |[nb](https://github.com/abjer/sds/b
 Aug 16|  9-12 | 7. Data structuring 3 | ABN|[nb](https://github.com/abjer/sds/blob/master/material/session_7/lecture_7.ipynb), [pdf](https://github.com/abjer/sds/blob/master/material/session_7/lecture_7.pdf) | [ex](https://github.com/abjer/sds/blob/master/material/session_7/exercise_7.ipynb),[sol](https://github.com/abjer/sds/blob/master/material/session_7/exercise_7_sol.ipynb)
 Aug 16| 13-16 | 8. Scraping 1 | SR |[nb](https://github.com/abjer/sds/blob/master/material/session_8/lecture_8.ipynb), [pdf](https://github.com/abjer/sds/blob/master/material/session_8/lecture_8.pdf) | [ex](https://github.com/abjer/sds/blob/master/material/session_8/exercise_8.ipynb), [sol](https://github.com/abjer/sds/blob/master/material/session_8/exercise_8_sol.ipynb)
 Aug 17|  9-12 | 9. Scraping 2 | SR | [nb](https://github.com/abjer/sds/blob/master/material/session_9/lecture_9.ipynb), [pdf](https://github.com/abjer/sds/blob/master/material/session_9/lecture_9.pdf)| [ex](https://github.com/abjer/sds/blob/master/material/session_9/exercise_9.ipynb)
-Aug 17| 13-.. | 10a. Big Data Intro | DDL | [ppt](https://github.com/abjer/sds/blob/master/material/session_10/lecture_10a.ppt), [pdf](https://github.com/abjer/sds/blob/master/material/session_10/lecture_10a.pdf) |
-Aug 17| ..-16 | 10b. Ethics | DDL | [ppt](https://github.com/abjer/sds/blob/master/material/session_10/lecture_10b.ppt), [pdf](https://github.com/abjer/sds/blob/master/material/session_10/lecture_10b.pdf) |
+Aug 17| 13-.. | 10a. Big Data Intro | DDL | [pptx](https://github.com/abjer/sds/blob/master/material/session_10/lecture_10a.pptx), [pdf](https://github.com/abjer/sds/blob/master/material/session_10/lecture_10a.pdf) |
+Aug 17| ..-16 | 10b. Ethics | DDL | [pptx](https://github.com/abjer/sds/blob/master/material/session_10/lecture_10b.pptx), [pdf](https://github.com/abjer/sds/blob/master/material/session_10/lecture_10b.pdf) |
       |       | ---------   Week 2  --------- | | |
 Aug 20|  9-12 | 11. Machine learning intro | ABN |  |
 Aug 20| 13-16 | 12. Supervised learning 1 | ABN | |
@@ -68,4 +68,4 @@ Aug 28| 13-16 |  *(brainstorm & supervision)* | TAs | |
 - ex: Exercise ready to be made
 - sol: Solution for exercise (Without solutions to the exercises you have to hand in)
 - key: Slides in Apple Keynote format
-- ppt: PowerPoint slides
+- pptx: PowerPoint slides