Concurrency: Add useful resources

Author: mincong-h

concurrency/README.md

@@ -4,9 +4,21 @@ Demonstrations:
 
 - `java.util.concurrent.CompletableFuture`
 
-## References
+## Useful Resources
 
-- Baeldung, "Guide To CompletableFuture", _baeldung.com_, 2020.
+Completable Future:
+
+- Baeldung, "Guide To CompletableFuture", _baeldung.com_, 2020.<br>
   <https://www.baeldung.com/java-completablefuture>
-- Lukáš Křečan, "CompletableFutures - why to using async methods?", _blog.krecan.net_, 2013.
+- Lukáš Křečan, "CompletableFutures - why to using async methods?", _blog.krecan.net_, 2013.<br>
   <https://blog.krecan.net/2013/12/25/completablefutures-why-to-use-async-methods/>
+
+General:
+
+- <https://typelevel.org/cats-effect/concurrency/>
+
+Thread Pool:
+
+- <https://monix.io/docs/3x/best-practices/blocking.html>
+- Daniel Spiewak, "Thread Pools", _github.com_, 2020.<br>
+  <https://gist.github.com/djspiewak/46b543800958cf61af6efa8e072bfd5c>