diff --git a/free-programming-books.md b/free-programming-books.md
index 8d719b433d68333fdff122cad686315cd7b451c0..6a331f5c6d7915a81776c0f750c0d254586ac979 100644
--- a/free-programming-books.md
+++ b/free-programming-books.md
@@ -441,7 +441,7 @@
 * [Introduction to Parallel Computing](https://computing.llnl.gov/tutorials/parallel_comp/) - Blaise Barney
 * [Is Parallel Programming Hard, And, If So, What Can You Do About It?](http://kernel.org/pub/linux/kernel/people/paulmck/perfbook/perfbook.html)
 * [Programming on Parallel Machines; GPU, Multicore, Clusters and More](http://heather.cs.ucdavis.edu/parprocbook) - Norm Matloff
-
+* [Is Parallel Programming Hard, And, If So, What Can You Do About It?](https://www.kernel.org/pub/linux/kernel/people/paulmck/perfbook/perfbook.html) - Paul E. McKenney
 
 ####Professional Development
 * [Confessions of an IT Manager](http://download.red-gate.com/ebooks/DotNet/Confessions_IT_Manager.zip) *(RedGate, By Phil Factor)*
@@ -851,7 +851,7 @@
 * [The Haskell Road to Logic, Math and Programming](http://fldit-www.cs.uni-dortmund.de/~peter/PS07/HR.pdf) (PDF)
 * [Wikibook Haskell](http://en.wikibooks.org/wiki/Haskell)
 * [Yet Another Haskell Tutorial](http://hal3.name/docs/daume02yaht.pdf) (PDF)
-
+* [Parallel and Concurrent Programming in Haskell](http://chimera.labs.oreilly.com/books/1230000000929/index.html) -  Simon Marlow 
 
 ###HTML / CSS
 * [A beginner's guide to HTML&CSS](http://learn.shayhowe.com/html-css/)