diff --git a/ch04.asciidoc b/ch04.asciidoc
index 1562e8d2..3f23d556 100644
--- a/ch04.asciidoc
+++ b/ch04.asciidoc
@@ -552,7 +552,7 @@ Another method for making keys is _deterministic key generation_. Here you deriv
 
 [TIP]
 ====
-Wallets contain keys, not coins. The coins are stored on the blockchain in the form of transaction-outputs (often noted as _vout_ or _txout_). Each user has a wallet containing keys. Wallets are really keychains containing pairs of private/public keys (See <<public_key>>). Users sign transactions with the keys, thereby proving they own the transaction outputs (their coins). 
+Wallets contain keys, not coins. The coins are stored on the blockchain in the form of transaction-outputs (often noted as _vout_ or _txout_). Each user has a wallet containing keys. Wallets are really keychains containing pairs of private/public keys (See XREF-public_key]). Users sign transactions with the keys, thereby proving they own the transaction outputs (their coins). 
 ====
 
 [[random_wallet]]