diff --git a/pngzop-references.html b/pngzop-references.html
index 086b940ae..0b8d97579 100644
--- a/pngzop-references.html
+++ b/pngzop-references.html
@@ -1,6 +1,10 @@
 <html><head><title>Zopli references</title></head>
 <body>
+<h2>Zopfli references</h2>
+<ul>
+<li>
 <a href="https://code.google.com/p/zopfli/downloads/detail?name=Data_compression_using_Zopfli.pdf&can=2&q=">
 Data_compression_using_Zopfli.pdf</a>
+</ul>
 </body>
 </html>
