chap 12 tweak

ch12_mining.adoc

@@ -660,9 +660,9 @@ this case to vary the output of the SHA256 commitment to the phrase.
 
 To make a challenge out of this algorithm, let's set a target: find a
 phrase that produces a hexadecimal hash that starts with a zero.
-Fortunately, this isn't difficult, as shown in <<sha256_example_generator_output>>:
+Fortunately, this isn't difficult, as shown in <<sha256_example_generator_output2>>:
 
-[[sha256_example_generator_output]]
+[[sha256_example_generator_output2]]
 .Simple proof-of-work implementation
 ----
 $ for nonce in $( seq 100 ) ; do echo "Hello, world! $nonce" | sha256sum ; done
@@ -713,7 +713,7 @@ any possible outcome can be calculated in advance. Therefore, an outcome
 of specified difficulty constitutes proof of a specific amount of work.
 ====
 
-In <<sha256_example_generator_output>>, the winning "nonce" is 32 and
+In <<sha256_example_generator_output2>>, the winning "nonce" is 32 and
 this result can be confirmed by anyone independently. Anyone can add the
 number 32 as a suffix to the phrase "Hello, world!" and compute
 the hash, verifying that it is less than the target:
@@ -740,7 +740,7 @@ below the target. The target and difficulty are inversely related.
 ====
 
 Bitcoin's Proof-of-Work is very similar to the challenge
-shown in <<sha256_example_generator_output>>. The miner constructs a
+shown in <<sha256_example_generator_output2>>. The miner constructs a
 candidate block filled with transactions. Next, the miner calculates the
 hash of this block's header and sees if it is smaller than the current
 _target_. If the hash is not less than the target, the miner will modify