diff --git a/ch12.asciidoc b/ch12.asciidoc
index f1efe287..4243c60f 100644
--- a/ch12.asciidoc
+++ b/ch12.asciidoc
@@ -110,7 +110,7 @@ In order to correctly interpret the metadata in a colored coins transaction you
 
 As an example, I created and issued a MasterBTC asset using colored coins. The MasterBTC asset represents a voucher for a free copy of this book. These vouchers can be transferred, traded, and redeemed using a colored coins-compatible wallet.
 
-For this particular example, I used the wallet and explorer at http://coinprism.info/[https://coinprism.info], which uses the Open Assets colored coins protocol.
+For this particular example, I used the wallet and explorer at http://coinprism.info/[_https://coinprism.info_], which uses the Open Assets colored coins protocol.
 
 <<the_issuance_transaction_as_viewed_on_coinprismio>> shows the issuance transaction using the Coinprism block explorer: