diff --git a/notes/todo.md b/notes/todo.md
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--- a/notes/todo.md
+++ b/notes/todo.md
@@ -1,10 +1,17 @@
 # To do
 
+## Research
+
+- [ ] Review CHIP-8
+    - read about the spec / ISA
+    - read these, and add them to the bibliography:
+        - Steve Losh: https://stevelosh.com/blog/2016/12/chip8-input/
+        - https://tonisagrista.com/blog/2021/chip8-spec/
+
 ## Misc
 
 - [ ] Play with JSDoc
 
-
 ## Design
 
 - [ ] Add keypad to memory map