diff --git a/book/source/06-certifications.md b/book/source/06-certifications.md
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--- a/book/source/06-certifications.md
+++ b/book/source/06-certifications.md
@@ -19,11 +19,13 @@ In this chapter, one important distinction is between:
 - Self-signatures, where the owner of a certificate uses signatures internal to their certificate and
 - Third-party signatures, where a third party issues statements about components of a certificate.
 
-## Terminology
+```{figure} mermaid/06-terminology.png
 
-```{include} mermaid/06-terminology.md
+Types of signatures in OpenPGP
 ```
 
+## Terminology
+
 The term *signature* can have multiple meanings in the context of the OpenPGP specification.
 Cryptographic keys create raw signatures which are byte sequences calculated according to some signature scheme.
 OpenPGP packs these raw signatures up into OpenPGP signature packets, which carry additional information in the form of signature subpackets.
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