diff --git a/trunk/doc/tor-design.tex b/trunk/doc/tor-design.tex
index 2305e71d17..b57234eb1f 100644
--- a/trunk/doc/tor-design.tex
+++ b/trunk/doc/tor-design.tex
@@ -318,8 +318,7 @@ encryption, so any node on a circuit can read that circuit's traffic.
 
 {\bf Hordes} \cite{hordes-jcs} is based on Crowds but also uses multicast
 responses to hide the initiator. {\bf Herbivore} \cite{herbivore} and
-{\bf P5} \cite{p5} go even further, requiring broadcast.
-% XXX This should be $P^5$ in bold. How to do it? -RD
+$\mbox{\bf P}^{\mathbf 5}$ \cite{p5} go even further, requiring broadcast.
 These systems are designed primarily for communication between peers,
 although Herbivore users can make external connections by
 requesting a peer to serve as a proxy.