diff --git a/ch09_fees.adoc b/ch09_fees.adoc
index ef3f7e35..5b8ab542 100644
--- a/ch09_fees.adoc
+++ b/ch09_fees.adoc
@@ -17,7 +17,7 @@ blockchain to a sufficient depth before he considers the money he
 received as his to spend (see <<confirmations>>).
 For Alice's transaction to be included in the
 blockchain, it must be included in a _block_ of transactions.  There are
-a limited number of blocks produced in a given amount of time and each
+a limited number of((("blocks", "transactions in")))((("transactions", "in blocks", secondary-sortas="blocks"))) blocks produced in a given amount of time and each
 block only has a limited amount of space.  Only the miner who creates
 that block gets to choose which transactions to include.  Miners may
 select transactions by any criteria they want, including refusing to