diff --git a/ch12_mining.adoc b/ch12_mining.adoc
index 61aa3fd2..1506cccd 100644
--- a/ch12_mining.adoc
+++ b/ch12_mining.adoc
@@ -1222,7 +1222,7 @@ forks (in addition to other problems), so many people prefer Bitcoin's
 
 === Mining and the Hash Lottery
 
-Bitcoin mining is an extremely competitive industry.
+Bitcoin mining ((("bitcoins", "mining", "competitiveness of", id="bitcoin-mining-competition")))((("mining", "competitiveness of", id="mining-competitive")))is an extremely competitive industry.
 The hashing power has increased exponentially every year of Bitcoin's
 existence. Some years the growth has reflected a complete change of
 technology, such as in 2010 and 2011 when many miners switched from
@@ -1461,7 +1461,7 @@ attack problem for Bitcoin itself. Rather, P2Pool makes Bitcoin more
 robust overall, as part of a diversified mining ecosystem.  As of this
 writing, P2Pool has fallen into disuse, but new protocols such as
 Stratum v2 can allow individual miners to choose the transactions they
-include in their blocks.
+include in their((("bitcoins", "mining", "competitiveness of", startref="bitcoin-mining-competition")))((("mining", "competitiveness of", startref="mining-competitive"))) blocks.
 
 [[consensus_attacks]]
 === Hashrate Attacks