update dp reference

book/imitation.html

@@ -351,7 +351,7 @@ <h1><a href="index.html" style="text-decoration:none;">Underactuated Robotics</a
     <p>One particularly successful form of behavior cloning for visuomotor
     policies with continuous action spaces is the <a
     href="https://diffusion-policy.cs.columbia.edu/">Diffusion Policy</a>
-    <elib>Chi23</elib>. The dexterous manipulation team at TRI had been working
+    <elib>Chi24</elib>. The dexterous manipulation team at TRI had been working
     on behavior cloning for some time, but the Diffusion Policy (which started
     as a summer internship project!) architecture has allowed us to very
     reliably train <a
@@ -801,12 +801,6 @@ <h1><a href="index.html" style="text-decoration:none;">Underactuated Robotics</a
 <span class="title">"Universal Manipulation Interface: In-The-Wild Robot Teaching Without In-The-Wild Robots"</span>, 
 , <span class="year">2024</span>.
 
-</li><br>
-<li id=Chi23>
-<span class="author">Cheng Chi and Siyuan Feng and Yilun Du and Zhenjia Xu and Eric Cousineau and Benjamin Burchfiel and Shuran Song</span>, 
-<span class="title">"Diffusion Policy: Visuomotor Policy Learning via Action Diffusion"</span>, 
-<span class="publisher">Proceedings of Robotics: Science and Systems</span> , <span class="year">2023</span>.
-
 </li><br>
 <li id=Nakkiran24>
 <span class="author">Preetum Nakkiran and Arwen Bradley and Hattie Zhou and Madhu Advani</span>,