add eth reference

cmingxu · cmingxu · commit 106a949b088f · 2019-04-17T20:30:17.000+08:00
Signed-off-by: xuchunming &lt;cming.xu@gmail.com&gt;
diff --git a/REFERENCE b/REFERENCE
@@ -18,3 +18,5 @@ https://bitcointechtalk.com/whats-new-in-bitcoin-core-v0-15-part-4-7c01c553783e
 
 # Very detailed explain what is account
 https://en.bitcoin.it/wiki/Help:Accounts_explained
+
+https://goethereumbook.org/client-setup/
