diff --git a/ch04.asciidoc b/ch04.asciidoc
index 0b4d3da7..6e46b9c1 100644
--- a/ch04.asciidoc
+++ b/ch04.asciidoc
@@ -640,7 +640,7 @@ A pay-to-script hash address is created from a transaction script, which defines
 script hash = RIPEMD160(SHA256(script))
 ----
     
-((("script hashes")))The resulting "script hash" is encoded with Base58Check with a version prefix of 5, which results in an encoded address starting with a +3+. An example of a P2SH address is +3F6i6kwkevjR7AsAd4te2YB2zZyASEm1HM+, which can be derived using the Bitcoin Explorer commands((("Bitcoin Explorer","script-encode command")))((("script-encode command (bx)"))) +script-encode+,((("Bitcoin Explorer","sha256 command")))((("sha256 command (bx)"))) +sha256+,((("Bitcoin Explorer","ripemd160 command")))((("ripemd160 command (bx)"))) +ripemd160+, and((("Bitcoin Explorer","base58check-encode command")))((("base58check-encode command (bx)"))) +base58check-encode+ (see <<libbitcoin>>) as follows:
+((("script hashes")))The resulting "script hash" is encoded with Base58Check with a version prefix of 5, which results in an encoded address starting with a +3+. An example of a P2SH address is +3F6i6kwkevjR7AsAd4te2YB2zZyASEm1HM+, which can be derived using the Bitcoin Explorer commands((("Bitcoin Explorer","script-encode command")))((("script-encode command (bx)"))) +script-encode+,((("Bitcoin Explorer","sha256 command")))((("sha256 command (bx)"))) +sha256+,((("Bitcoin Explorer","ripemd160 command")))((("ripemd160 command (bx)"))) +ripemd160+, and((("Bitcoin Explorer","base58check-encode command")))((("base58check-encode command (bx)"))) +base58check-encode+ (see <<appdx_bx>>) as follows:
 
 ----
 $ echo dup hash160 [ 89abcdefabbaabbaabbaabbaabbaabbaabbaabba ] equalverify checksig > script