diff --git a/ch04_keys.adoc b/ch04_keys.adoc
index 65ad7034..65c80b57 100644
--- a/ch04_keys.adoc
+++ b/ch04_keys.adoc
@@ -853,7 +853,7 @@ compressed public keys.
 [[addresses_for_p2sh]]
 === Legacy Pay to Script Hash (P2SH)
 
-As we've seen in preceding sections, someone receiving bitcoins (like
+As we've ((("public key cryptography", "hash functions and", id="pub-key-hash2")))((("hash functions", "Bitcoin payments and", id="hash-payment2")))((("payments", "with hash functions", secondary-sortas="hash functions", id="payment-hash2")))((("P2SH (pay to script hash)", id="p2sh")))seen in preceding sections, someone receiving bitcoins (like
 Bob) can require that payments to him contain certain constraints in their
 output script.  Bob will need to fulfill those constraints using an
 input script when he spends those bitcoins.  In <<p2pk>>, the constraint
@@ -994,7 +994,7 @@ Bitcoin miners about 32 billion years.
 
 Although we do not believe there is any immediate threat to anyone
 creating new P2SH addresses, we recommend all new wallets use newer
-types of addresses to eliminate address collision attacks as a concern.
+types of addresses to eliminate address collision attacks((("public key cryptography", "hash functions and", startref="pub-key-hash2")))((("hash functions", "Bitcoin payments and", startref="hash-payment2")))((("payments", "with hash functions", secondary-sortas="hash functions", startref="payment-hash2")))((("P2SH (pay to script hash)", startref="p2sh"))) as a concern.
 ****
 
 === Bech32 Addresses