diff --git a/book/source/04-certificates.md b/book/source/04-certificates.md
index 297cc0b..7b2f3a1 100644
--- a/book/source/04-certificates.md
+++ b/book/source/04-certificates.md
@@ -169,6 +169,12 @@ Minimized versions, merging, effective "append only" semantics, ...
 
 ### How to generate "minimized" certificate?
 
+### When are certificates valid?
+
+- Full certificate: Primary revoked/key expired/binding signature expired,
+- Subkey: Revoked/key expired/binding signature expired
+- User ID: revoked, binding expired, ...
+
 ### Best Practices regarding Key Freshness
 
 - Expiry
diff --git a/book/source/09-verification.md b/book/source/09-verification.md
index 821f4ab..5223ac5 100644
--- a/book/source/09-verification.md
+++ b/book/source/09-verification.md
@@ -1,13 +1,9 @@
 # Verification
 
-```
   - Self-authenticating data (unhashed subpackets)
 
 ## When are signatures valid?
-  - Validity as a tree of signatures
 
-## When are certificates valid?
+- Validity as a tree of signatures
 
-Primary revoked, User ID revoked, ...
-Which signatures take precendence?
-```
\ No newline at end of file
+## Which signatures take precedence?