diff --git a/src/teaching/cse-562/2021sp/slide/2021-02-09-RA-Basics-and-Spark.erb b/src/teaching/cse-562/2021sp/slide/2021-02-09-RA-Basics-and-Spark.erb
index c46ce588..53bde0d4 100644
--- a/src/teaching/cse-562/2021sp/slide/2021-02-09-RA-Basics-and-Spark.erb
+++ b/src/teaching/cse-562/2021sp/slide/2021-02-09-RA-Basics-and-Spark.erb
@@ -26,7 +26,7 @@ textbook: "Ch. 2.4, 5.1"
         <li>How can we tell if <b>[Query B]</b> is better than <b>[Query A]</b>?</li>
       </ol>
     </p>   
-    <p class="fragment">... but first let';s remind ourselves of few definitions.</p>             
+    <p class="fragment">... but first let's remind ourselves of few definitions.</p>             
   </section>
 
   <section>
@@ -34,7 +34,7 @@ textbook: "Ch. 2.4, 5.1"
 
     <dl>
       <dt>Relation (Table)</dt>
-      <dd>A collection of Tuples of Values</dd>
+      <dd>A collection of Tuples of Primitive Values</dd>
       <dd>All tuples have the same set of attributes, or schema</dd>
     </dl>
   </section>
@@ -340,7 +340,7 @@ For each week:
     <h3>Intersection ($\cap$)</h3>
     <p>Return all tuples appearing in <u>both</u> <br/>of two union-compatible relations</p>
     <div class="fragment" style="font-size: 70%;">
-      $$(\sigma_{(BORONAME=\texttt{'Brooklyn'})} (\pi_{SPC\_COMMON} \textbf{Trees})) \\ ~~~~~~~~~\cap (\sigma_{(BORONAME=\texttt{'Manhattan'})} (\pi_{SPC\_COMMON} \textbf{Trees}))$$
+      $$(\pi_{SPC\_COMMON} ( \sigma_{(BORONAME=\texttt{'Brooklyn'})} \textbf{Trees}))\\ ~~~~~~~~~\cap  (\pi_{SPC\_COMMON} (\sigma_{(BORONAME=\texttt{'Manhattan'})} \textbf{Trees}))$$
       <p>What is this query asking?</p>
     </div>
   </section>
diff --git a/templates/cse4562_2021_slides.erb b/templates/cse4562_2021_slides.erb
index 3d62afd0..f810a85d 100644
--- a/templates/cse4562_2021_slides.erb
+++ b/templates/cse4562_2021_slides.erb
@@ -55,7 +55,7 @@ class_name = "CSE-4/562 Spring 2021"
         <h4><%= class_name %></h4>
         <p><%= date %></p>
         <% if defined? textbook %>
-        <h5><b>Textbook</b>: <%= textbook %></h5>
+        <h5><b>Garcia-Molina/Ullman/Widom</b>: <%= textbook %></h5>
         <% end %>
       </section>