diff --git a/index_tags.md b/index_tags.md
index e4f166e2..9f52da81 100644
--- a/index_tags.md
+++ b/index_tags.md
@@ -49,6 +49,8 @@ but also chapters and tags. The `Tag` elements add important metadata to identif
 in a Matroska `Segment`. It can tag a whole `Segment`, separate `Tracks` elements, individual `Chapter` elements or `Attachments` elements.
 
 Some details about tagging are already present in [@!RFC9559, section 24].
+Readers of this document should be familiar with that section, the different high level parts of Matroska as defined in in [@!RFC9559, section 4.5]
+and EBML Master Elements as defined in in [@!RFC8794, section 7.7].
 
 While the Matroska tagging framework allows anyone to create their own custom tags, it's important to have a common
 set of values for interoperability. This document intends to define a set of common tag names used in Matroska.