diff --git a/src/teaching/cse-562/2017sp/index.erb b/src/teaching/cse-562/2017sp/index.erb
index 4b70fbc3..15d0720b 100644
--- a/src/teaching/cse-562/2017sp/index.erb
+++ b/src/teaching/cse-562/2017sp/index.erb
@@ -40,11 +40,14 @@ classContent:
       board: slides/2017-02-16-Board.pdf
       video: https://youtu.be/MxFnwTnW0a0
   - date: Feb. 21
-    topic: Joins and Aggregation Algorithms
+    topic: External and Aggregation Algorithms
+    meta:
+      notes: slides/2017-02-21-ExternalAlgos.pdf
+      board: slides/2017-02-21-Board.pdf
   - date: Feb. 23
-    topic: Join Algorithms
+    topic: Joins and Join Algorithms
   - date: Feb. 28
-    topic: Memory Hierarchy-Aware Algorithms
+    topic: Relational Algebra and Optimization
   - date: Mar. 2
     topic: Relational Algebra and Optimization
   - date: Mar. 7
diff --git a/src/teaching/cse-562/2017sp/slides/2017-02-21-Board.pdf b/src/teaching/cse-562/2017sp/slides/2017-02-21-Board.pdf
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diff --git a/src/teaching/cse-562/2017sp/slides/2017-02-21-ExternalAlgos.pdf b/src/teaching/cse-562/2017sp/slides/2017-02-21-ExternalAlgos.pdf
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