diff --git a/ch05.asciidoc b/ch05.asciidoc
index a7b65207..7da09dcb 100644
--- a/ch05.asciidoc
+++ b/ch05.asciidoc
@@ -84,7 +84,7 @@ garbage claim echo media make crunch
 
 ==== Wallet Best Practices
 
-((("wallets", "best practices for")))As bitcoin wallet technology has matured, certain common industry standards have emerged that make bitcoin wallets broadly interoperable, easy to use, secure, and flexible. These common standards are:
+((("wallets", "best practices for")))((("bitcoin improvement proposals", "Multipurpose HD Wallet Structure (BIP-43)")))As bitcoin wallet technology has matured, certain common industry standards have emerged that make bitcoin wallets broadly interoperable, easy to use, secure, and flexible. These common standards are:
 
 * Mnemonic code words, based on BIP-39
 * Hierarchical deterministic wallets, based on BIP-32