diff --git a/TODO b/TODO
index b45c784..34bb201 100644
--- a/TODO
+++ b/TODO
@@ -153,3 +153,38 @@ https://hello-rust.show/9/
 ---- Kubernetes
 
 https://medium.com/pinterest-engineering/building-a-kubernetes-platform-at-pinterest-fb3d9571c948
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+Elevator Systems
+https://www.youtube.com/watch?v=BCN9mQOT3RQ
+https://www.youtube.com/watch?v=oY1QlCqWOss
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+Linux Kernel With Tracing
+https://www.youtube.com/watch?v=JRyrhsx-L5Y
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+Linux Kernel Debugging
+https://www.youtube.com/watch?v=Ni_FuuYmsHw
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+The Tragedy of systemd
+https://www.youtube.com/watch?v=o_AIw9bGogo
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+Transaction Theory
+http://faculty.juniata.edu/rhodes/dbms/transproc.htm
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+Redis Transactions
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+https://erichohenstein.com/2016/01/redis-transactions/
+Interesting -> Redis asks the client to specify keys to be watched during a transaction (to avoid concurrent access)
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+https://nathanmlong.com/2015/10/reimplementing-rubys-hash/
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+Data Structures
+https://www.youtube.com/watch?v=tvyAx-JI7sM
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+Interviewing
+https://thinksoftware.medium.com/elevator-system-design-a-tricky-technical-interview-question-116f396f2b1c