link lecture 8

docs/index.md

@@ -32,8 +32,9 @@ If something is unclear, if you notice a typo, or if you have a suggestion, plea
   (based on chapters 17–18)  
   Exercises 17.1–17.4, 18.1, 18.2
 
-* Week 8: Magnetism  
-  (based on chapters 19-20)
+* Week 8: [Magnetism](lecture_8.md)  
+  (based on chapters 19-20)  
+  Exercises 19.3, 19.6, 20.1, 20.4
 
 ## Test results
 

mkdocs.yml

@@ -13,7 +13,7 @@ pages:
   - Crystal structure and diffraction: 'lecture_5.md'
   - Tight binding and nearly free electrons: 'lecture_6.md'
   - Semiconductors: 'lecture_7.md'
-      # - Magnetism
+  - Magnetism: 'lecture_8.md'
 
 theme:
   name: material