diff --git a/ch03.asciidoc b/ch03.asciidoc
index ae3d7767..b40f1148 100644
--- a/ch03.asciidoc
+++ b/ch03.asciidoc
@@ -615,9 +615,9 @@ We can further explore the blockchain by examining the previous transaction refe
 
 ==== Exploring Blocks
 
-Commands: +getblock+, +getblockhash+
+((("Bitcoin Core", "Bitcoin Core API", "exploring blocks")))((("blocks", "exploring with Bitcoin Core API")))Commands: +getblock+, +getblockhash+
 
-Exploring blocks is similar to exploring transactions. However, blocks can be referenced either by the block _height_ or by the block _hash_. First, let's find a block by its height. In <<cup_of_coffee>>, we saw that Alice's transaction was included in block 277316.
+((("blocks", "block height")))((("blocks", "block hash")))Exploring blocks is similar to exploring transactions. However, blocks can be referenced either by the block _height_ or by the block _hash_. First, let's find a block by its height. In <<cup_of_coffee>>, we saw that Alice's transaction was included in block 277316.
 
 We use the +getblockhash+ command, which takes the block height as the parameter and returns the block hash for that block: