Merge branch 'main' into upd-website

Author: mmcky

website/index.html

@@ -22,6 +22,8 @@
             <h1><b>Dynamic Programming</b></h1>
             <br>
             <a href="http://www.tomsargent.com/">Thomas J. Sargent</a> and <a href="http://johnstachurski.net/">John Stachurski</a>
+            <br><br>
+            <a href="https://www.amazon.com/Dynamic-Programming-Finite-Thomas-Sargent/dp/1009540750/">Amazon</a>
         </div>
         <div class="amazon-link-container">
             <a href="https://www.amazon.com/Dynamic-Programming-Finite-Thomas-Sargent/dp/1009540750/" class="amazon-button">📚 Buy on Amazon</a>