diff --git a/ch09_fees.adoc b/ch09_fees.adoc
index 1dca57e0..ef3f7e35 100644
--- a/ch09_fees.adoc
+++ b/ch09_fees.adoc
@@ -6,7 +6,7 @@ proves that she knows her private key and that she committed to a
 transaction that pays Bob.  She can create another signature that
 instead commits to a transaction paying Carol--a transaction that spends
 the same output (bitcoins) that she used to pay Bob.  Those two
-transactions are now _conflicting transactions_ because only one
+transactions((("conflicting transactions")))((("transactions", "conflicts in"))) are now _conflicting transactions_ because only one
 transaction spending a particular output can be included in the valid
 blockchain with the most proof of work--the blockchain that full nodes
 use to determine which keys control which bitcoins.