diff --git a/ch02_overview.adoc b/ch02_overview.adoc
index bede6dd0..c8eb8ea2 100644
--- a/ch02_overview.adoc
+++ b/ch02_overview.adoc
@@ -446,7 +446,7 @@ wallet can further verify Alice's transaction only spends((("transactions", "con
 
 === Bitcoin Mining
 
-Alice's transaction((("bitcoins", "mining", "operational overview", id="bitcoin-mining-operational-overview")))((("mining", "operational overview", id="mining-operational-overview"))) is now propagated on the Bitcoin
+Alice's transaction((("mining", "operational overview", id="mining-operational-overview"))) is now propagated on the Bitcoin
 network. It does not become part of the _blockchain_ until it is
 included in a block by a process called _mining_ and that block has been
 validated by full nodes. See
@@ -585,7 +585,7 @@ computation difficulty for the chain as a whole.
 By convention, any block with more than six confirmations
 is considered very hard to change, because it would require an immense amount of
 computation to recalculate six blocks (plus one new block). We will examine
-the process of mining and the way it builds confidence in more ((("bitcoins", "mining", "operational overview", startref="bitcoin-mining-operational-overview")))((("mining", "operational overview", startref="mining-operational-overview")))detail in
+the process of mining and the way it builds confidence in more ((("mining", "operational overview", startref="mining-operational-overview")))detail in
 <<mining>>.
 
 [[block-alice1]]