diff --git a/selected/compilers.md b/selected/compilers.md
index 5ae6912..f6e946c 100644
--- a/selected/compilers.md
+++ b/selected/compilers.md
@@ -54,15 +54,14 @@ ok what do we want to cover
 |    | V: Compiler Design SA         | https://www.youtube.com/watch?v=57U6pQRnSJA |
 |    | V: Semantic Analysis: Intro   | https://www.youtube.com/watch?v=7pHmBEkeIdQ |
 
-| Title                            | Page |
-|----------------------------------|------|
-| Type Checking in Compiler Design | https://www.geeksforgeeks.org/type-checking-in-compiler-design/ |
-| Type Checking                    | https://www.brainkart.com/article/Type-Checking_8086/ |
-| Type Checking (Slides)           | https://www.slideshare.net/dipongkersen81/type-checkingcompilier-design |
-| What is Static Type Checking?    | https://www.tutorialspoint.com/what-is-static-type-checking |
-| Type Checking in Compiler Design | https://www.wikitechy.com/tutorials/compiler-design/type-checking-in-compiler-design |
-| Type Systems                     | https://www.csd.uwo.ca/~mmorenom/CS447/Lectures/TypeChecking.html/node1.html |
-| V: Type Checking                 | https://www.youtube.com/watch?v=-TQVAKby6oI |
+|Star| Title                            | Page |
+|----|----------------------------------|------|
+|    | Type Checking in Compiler Design | https://www.geeksforgeeks.org/type-checking-in-compiler-design/ |
+|    | Type Checking (Slides)           | https://www.slideshare.net/dipongkersen81/type-checkingcompilier-design |
+|    | What is Static Type Checking?    | https://www.tutorialspoint.com/what-is-static-type-checking |
+|    | What is Dynamic Type Checking?   | https://www.tutorialspoint.com/what-is-dynamic-type-checking |
+|    | Type Systems                     | https://www.csd.uwo.ca/~mmorenom/CS447/Lectures/TypeChecking.html/node1.html |
+|    | V: Type Checking                 | https://www.youtube.com/watch?v=-TQVAKby6oI |
 
 - modern compiler structures (IR / SSA, optimization)