diff --git a/docs/PTHInternals.html b/docs/PTHInternals.html
index 279d479..b15f681 100644
--- a/docs/PTHInternals.html
+++ b/docs/PTHInternals.html
@@ -1,8 +1,10 @@
+<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01//EN"
+          "http://www.w3.org/TR/html4/strict.dtd">
 <html>
   <head>
   <title>Pretokenized Headers (PTH)</title>
-  <link type="text/css" rel="stylesheet" href="../menu.css" />
-  <link type="text/css" rel="stylesheet" href="../content.css" />
+  <link type="text/css" rel="stylesheet" href="../menu.css">
+  <link type="text/css" rel="stylesheet" href="../content.css">
   <style type="text/css">
     td {
     vertical-align: top;