diff --git a/header.tpl b/header.tpl
index 530da25..fc3ea8e 100644
--- a/header.tpl
+++ b/header.tpl
@@ -179,7 +179,8 @@
       </div>
       <div class="menu-item">
         <img class="top-icon" src="img/update-icon.svg" alt="update icon"/>
-        <a href="https://github.com/NullHypothesis/censorbib/commits/master">Last update: 2019-12-14</a>
+        <a
+        href="https://github.com/NullHypothesis/censorbib/commits/master">Last update: 2020-01-26</a>
       </div>
       <div class="menu-item">
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diff --git a/references.bib b/references.bib
index aff1a24..50a2c33 100644
--- a/references.bib
+++ b/references.bib
@@ -1,3 +1,11 @@
+@techreport{Appelbaum2012a,
+	author = {Jacob Appelbaum},
+	title = {Technical analysis of the {Ultrasurf} proxying software},
+	institution = {The Tor Project},
+	year = {2012},
+	url = {https://media.torproject.org/misc/2012-04-16-ultrasurf-analysis.pdf},
+}
+
 @inproceedings{Frolov2019b,
 	author = {Sergey Frolov and Jack Wampler and Sze Chuen Tan and J. Alex Halderman and Nikita Borisov and Eric Wustrow},
 	title = {{Conjure}: Summoning Proxies from Unused Address Space},