diff --git a/book/source/04-certificates.md b/book/source/04-certificates.md
index 254afc9..ae03ec1 100644
--- a/book/source/04-certificates.md
+++ b/book/source/04-certificates.md
@@ -224,6 +224,7 @@ This section needs to be written
 
 Third-party identity certifications have historically played a pivotal role in the OpenPGP ecosystem. 
 
+(cert-flooding)=
 ### Security considerations
 
 While a convenience for consumers, indiscriminately accepting and integrating third-party identity certifications comes with significant risks.