diff --git a/slides/cse4562sp2018/2018-02-14-ExtRA.html b/slides/cse4562sp2018/2018-02-14-ExtRA.html
index 5ac94534..61af84f8 100644
--- a/slides/cse4562sp2018/2018-02-14-ExtRA.html
+++ b/slides/cse4562sp2018/2018-02-14-ExtRA.html
@@ -77,6 +77,12 @@
           </dl>
         </section>
 
+        <section>
+          <h3>Outer Join</h3>
+        </section>
+      </section>
+
+      <section>
         <section>
           <h3>Sort / Limit</h3>
 
@@ -93,8 +99,28 @@
         </section>
 
         <section>
-          <h3>Distinct</h3>
+          <h3>Sort</h3>
 
+          <p style="margin-top: 100px;">
+            Pick your favorite sort algorithm.
+          </p>
+
+          <p class="fragment">What happens if you don't have enough memory?</p>
+        </section>
+
+        <section>
+          <p><b>Key Idea:</b> Merging 2 sorted lists requires $O(1)$ memory.</p>
+        </section>
+
+        <section>
+          <h3>2-Way Sort</h3>
+          <dl>
+            <dt>Pass 1</dt>
+            <dd>Create lots of (small) sorted lists.</dd>
+
+            <dt>Pass 2+</dt>
+            <dd>Merge sorted lists of size $N$ into sorted lists of size $2N$</dd>
+          </dl>
         </section>
       </section>