diff --git a/10_onion_routing.asciidoc b/10_onion_routing.asciidoc
index f83a9f9..ce648f0 100644
--- a/10_onion_routing.asciidoc
+++ b/10_onion_routing.asciidoc
@@ -13,7 +13,7 @@ Onion routing describes a method of encrypted communication where a message send
 
 Each of the intermediary nodes can only "peel" one layer and see who is next in the communication path. Onion routing ensures that no one except the sender knows the destination or length of the communication path. Each intermediary only knows the previous and next hop.
 
-The Lightning Network uses an implementation of onion routing protocol based on _Sphinx_footnote:[George Danezis and Ian Goldberg, "Sphinx: A Compact and Provably Secure Mix Format," in _IEEE Symposium on Security and Privacy_ (New York: IEEE, 2009), 269–282.] developed in 2009 by George Danezis and Ian Goldberg.
+The Lightning Network uses an implementation of onion routing protocol based on pass:[<em>Sphinx</em>]footnote:[George Danezis and Ian Goldberg, "Sphinx: A Compact and Provably Secure Mix Format," in _IEEE Symposium on Security and Privacy_ (New York: IEEE, 2009), 269–282.] developed in 2009 by George Danezis and Ian Goldberg.
 
 The implementation of onion routing in the Lightning Network is defined in https://github.com/lightningnetwork/lightning-rfc/blob/master/04-onion-routing.md[BOLT #4: Onion Routing Protocol].