diff --git a/ch05_wallets.adoc b/ch05_wallets.adoc
index 47d5f15f..7f12d450 100644
--- a/ch05_wallets.adoc
+++ b/ch05_wallets.adoc
@@ -1127,7 +1127,7 @@ operate exactly((("key generation", "HD (hierarchical deterministic)", "private
 ===== Extended keys
 
 As
-we saw earlier, the key derivation function can be used to create
+we saw ((("key generation", "HD (hierarchical deterministic)", "extended keys", id="keygen-hd-extend")))((("HD (hierarchical deterministic) key generation", "extended keys", id="hd-keygen-extend")))((("extended keys", id="extend-key")))earlier, the key derivation function can be used to create
 children at any level of the tree, based on the three inputs: a key, a
 chain code, and the index of the desired child. The two essential
 ingredients are the key and chain code, and combined these are called an