Removing some hard coded xrefs

ch04.asciidoc

@@ -786,7 +786,7 @@ On the fourth level "change", an HD wallet has two sub-trees, one for creating r
 
 ===== Experimenting with HD wallets using sx-tools
 
-Using the command line tool +sx+, introduced in chapter 3, you can experiment with generating and extending BIP0032 deterministic keys, as well as displaying them in different formats:
+Using the command line tool +sx+, introduced in <<ch03_bitcoin_client>>, you can experiment with generating and extending BIP0032 deterministic keys, as well as displaying them in different formats:
 
 ====
 [source, bash]
@@ -856,7 +856,7 @@ P2SH is not necessarily the same as a multi-signature standard transaction. A P2
 
 ===== Multi-signature addresses and P2SH
 
-Currently, the most common implementation of the P2SH function is the multi-signature address script. As the name implies, the underlying script requires more than one signature to prove ownership and therefore spend funds. The bitcoin multi-signature feature is designed to require M signatures (also known as the “threshold”) from a total of N keys, known as an M-of-N multi-sig, where M is equal to or less than N. For example, Bob the coffee shop owner from chapter 1 could use a multi-signature address requiring 1-of-2 signatures from a key belonging to him and a key belonging to his spouse, ensuring either of them could sign to spend a transaction output locked to this address. This would be similar to a “joint account” as implemented in traditional banking where either spouse can spend with a single signature. Or Gopesh, the web designer paid by Bob to create a website might have a 2-of-3 multi-signature address for his business that ensures that no funds can be spent unless at least two of the business partners sign a transaction. 
+Currently, the most common implementation of the P2SH function is the multi-signature address script. As the name implies, the underlying script requires more than one signature to prove ownership and therefore spend funds. The bitcoin multi-signature feature is designed to require M signatures (also known as the “threshold”) from a total of N keys, known as an M-of-N multi-sig, where M is equal to or less than N. For example, Bob the coffee shop owner from <<ch01_intro_what_is_bitcoin>> could use a multi-signature address requiring 1-of-2 signatures from a key belonging to him and a key belonging to his spouse, ensuring either of them could sign to spend a transaction output locked to this address. This would be similar to a “joint account” as implemented in traditional banking where either spouse can spend with a single signature. Or Gopesh, the web designer paid by Bob to create a website might have a 2-of-3 multi-signature address for his business that ensures that no funds can be spent unless at least two of the business partners sign a transaction. 
 
 We will explore how to create transactions that spend funds from P2SH (and multi-signature) addresses in <<transactions>>.
 

ch05.asciidoc

@@ -466,7 +466,7 @@ A standard transaction (one that conforms to the +isStandard()+ checks) can have
 
 Pay-to-Script-Hash (P2SH) was introduced in the winter of 2012 as a powerful new type of transaction that greatly simplifies the use of complex transaction scripts. To explain the need for P2SH, let's look at a practical example.
 
-In chapter 1 we introduced Mohammed, an electronics importer based in Dubai. Mohammed's company uses bitcoin's multi-signature feature extensively for its corporate accounts. Multi-signature scripts are one of the most common uses of bitcoin's advanced scripting capabilities and are a very powerful feature. Mohammed's company uses a multi-signature script for all customer payments, known in accounting terms as "accounts receivable" or AR. With the multi-signature scheme, any payments made by customers are locked in such a way that they require at least two signatures to release, from Mohammed and one of his partners or from his attorney who has a backup key. A multi-signature scheme like that offers corporate governance controls and protects against theft, embezzlement or loss. 
+In <<ch01_intro_what_is_bitcoin>> we introduced Mohammed, an electronics importer based in Dubai. Mohammed's company uses bitcoin's multi-signature feature extensively for its corporate accounts. Multi-signature scripts are one of the most common uses of bitcoin's advanced scripting capabilities and are a very powerful feature. Mohammed's company uses a multi-signature script for all customer payments, known in accounting terms as "accounts receivable" or AR. With the multi-signature scheme, any payments made by customers are locked in such a way that they require at least two signatures to release, from Mohammed and one of his partners or from his attorney who has a backup key. A multi-signature scheme like that offers corporate governance controls and protects against theft, embezzlement or loss. 
 
 The resulting script is quite long and looks like this:
 

ch08.asciidoc

@@ -117,7 +117,7 @@ By independently verifying each transaction as it is received and before propaga
 
 === Mining Nodes
 
-Some of the nodes on the bitcoin network are specialized nodes called _miners_. In Chapter 1 we introduced Jing, a computer engineering student in Shanghai, China, who is a bitcoin miner. Jing earns bitcoin by running a "mining rig", which is a specialized computer-hardware system designed to mine bitcoins. Jing's specialized mining hardware is connected to a server running a full bitcoin node. Unlike Jing, some miners mine without a full node as we will see in <<mining pools>>. Like every other full node, Jing's node receives and propagates unconfirmed transactions on the bitcoin network. Jing's node, however, also aggregates these transactions into new blocks.
+Some of the nodes on the bitcoin network are specialized nodes called _miners_. In <<ch01_intro_what_is_bitcoin>> we introduced Jing, a computer engineering student in Shanghai, China, who is a bitcoin miner. Jing earns bitcoin by running a "mining rig", which is a specialized computer-hardware system designed to mine bitcoins. Jing's specialized mining hardware is connected to a server running a full bitcoin node. Unlike Jing, some miners mine without a full node as we will see in <<mining pools>>. Like every other full node, Jing's node receives and propagates unconfirmed transactions on the bitcoin network. Jing's node, however, also aggregates these transactions into new blocks.
     
 Jing's node is listening for new blocks, propagated on the bitcoin network, as do all nodes. However, the arrival of a new block has special significance for a mining node. The competition among miners effectively ends with the propagation of a new block which acts as an announcement of a winner. To a miner, receiving a new block means someone else won the competition and they lost. However, the end of one round of a competition is also the beginning of the next round. The new block is not just a checkered flag, marking the end of the race, it is also the starting pistol starting the race for the next block.