diff --git a/ch03_bitcoin-core.adoc b/ch03_bitcoin-core.adoc
index 586b5d05..2122f25a 100644
--- a/ch03_bitcoin-core.adoc
+++ b/ch03_bitcoin-core.adoc
@@ -1032,7 +1032,7 @@ If you're implementing a JSON-RPC call in your own program, you can use
 a generic HTTP library to construct the call, similar to what is shown
 in the preceding +curl+ example.
 
-However, there are libraries in most popular programming languages that
+However, there ((("Bitcoin Core", "wrapper libraries")))((("wrapper libraries", "Bitcoin Core")))are libraries in most popular programming languages that
 "wrap" the Bitcoin Core API in a way that makes this a lot simpler. We
 will use the +python-bitcoinlib+ library to simplify API access.
 This library is not part of the Bitcoin Core project and needs to be