diff --git a/handbook/computing/getsurvex.html b/handbook/computing/getsurvex.html
index 50b5ca575..1086a6c78 100644
--- a/handbook/computing/getsurvex.html
+++ b/handbook/computing/getsurvex.html
@@ -32,9 +32,12 @@ convert your sketches into actual plan and elevation presentation-quality survey
<a href="http://expo.survex.com/expofiles/tunnelwiki/wiki/pages/Tunnel.html">TunnelX detailed wiki documentation (old)</a>.
<h2>Therion</h2>
-<p>
-<a href="https://therion.speleo.sk/">Therion</a>
+<a href="../l/therion-dataflow.html"><img class="onright" src="../t/therion-dataflow.jpg"></a>
+<br>
+<p>Article by Wookey: <a href="/expofiles/documents/therion-cp33.pdf"><em>Drawing Surveys with Therion</em></a> (Compass Points, March 2004)
+<p>
+<a href="https://therion.speleo.sk/">Therion website</a>
<h2>GPS stuff</h2>
<p>GPS is increasingly important for all the surface work.
diff --git a/handbook/computing/yourlaptop.html b/handbook/computing/yourlaptop.html
index 38ca3afb3..d525fafa4 100644
--- a/handbook/computing/yourlaptop.html
+++ b/handbook/computing/yourlaptop.html
@@ -181,6 +181,8 @@ where obviously you will be using your own locations for expofiles, expoweb, los
<ul>
<li>Using Survex, Tunnel and Therion, see the <a href="http://expo.survex.com/handbook/survey/">Expo Handbook - Surveying section</a>.
+<li><p><a href="/expofiles/documents/therion-cp33.pdf"><em>Drawing Surveys with Therion</em></a> (Wookey, Compass Points, March 2004)
+
<li><em>For installing Survex, Tunnel etc. see <a href="getsurvex.html">this page</a> which may be merged in here eventually.</em>
<li><a href="../../documents/tunnel-loefflerCP35-only.pdf">Introduction to using Tunnel</a> - article by Dave Loeffler. This is really good and should be read first.
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@@ -0,0 +1,28 @@
+<!DOCTYPE html>
+<html>
+<head>
+<meta http-equiv="Content-Type" content="text/html; charset=utf-8" />
+<title>CUCC Expo Handbook: Therion Dataflow</title>
+<link rel="stylesheet" type="text/css" href="../../css/main2.css" />
+</head>
+<body><style>body { background: #fff url(/images/style/bg-system.png) repeat-x 0 0 }</style>
+<h2 id="tophead">CUCC Expo Handbook - Therion Dataflow</h2>
+<h1>Therion Dataflow</h1>
+<style>figure {font-weight: bold; font-size: small; font-family: sans-serif;font-variant-caps: small-caps;}</style>
+
+
+
+<img src="../i/therion-dataflow.jpg" >
+
+<p>Diagram of how the components of Therion fit together. Programs
+are in boxes, other items are data files, arrows show data flow between
+programs. Files/programs related to Therion are shown in bold, input files
+created by the user and output files generated by Therion are in italics.
+
+<p>From article by Wookey: <a href="/expofiles/documents/therion-cp33.pdf"><em>Drawing Surveys with Therion</em></a> (Compass Points, March 2004)
+
+
+
+<hr />
+</body>
+</html>
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