Index: docs/weeks/4.md
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--- docs/weeks/4.md
+++ docs/weeks/4.md
@@ -1,8 +1,8 @@
 # Week 4
 
-**No lecture this week.**
+**No lecture on Monday, but we do have a special lecture on Thursday (see [week 5](5.md)).**
 
 ## Tutorial
 
 Homework
 : - Come up with a fictional research scenario and complete the [EFF risk assessment](https://ssd.eff.org/en/module/your-security-plan) for that hypothetical scenario. Think about what skills or tools you would need to mitigate the risks you identified.

Index: docs/weeks/5.md
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--- docs/weeks/5.md
+++ docs/weeks/5.md
@@ -1,8 +1,10 @@
 # Week 5
 
 ## Lecture
+
+**This lecture is scheduled for Thursday, May 6, at 14:30.**
 
 Readings
 : - Wouters (2017)
 - [Leiden Manifesto](http://www.leidenmanifesto.org/)