Improving README

Author: vtrbtf

README.md

@@ -4,16 +4,18 @@ My personal collection of algorithms and data structures :)
 
 ## Categories
 
-  - Classical  
+  - Classical
+  - Advanced Algorithms and Data Structures
   - Graph
   - Sequence
   - Statistics
   - Cryptography
-  - Machine learning 
+  - Machine learning
   - Language theory
   - Cache
   - Hashes
   - Distributed systems
+  - HackerRank
   - Misc
 
 ## References
@@ -30,3 +32,7 @@ My personal collection of algorithms and data structures :)
 ### Books
   - [Programming Pearls](http://www.amazon.com/Programming-Pearls-2nd-Edition-Bentley/dp/0201657880)
   - [Algorithms, 4th Edition](http://algs4.cs.princeton.edu/home/)
+  - [Introduction to Distributed Algorithms](http://www.amazon.com/Introduction-Distributed-Algorithms-Gerard-Tel/dp/0521794838)
+  - [150 Programming Questions and Solutions by Gayle Laakmann](http://www.amazon.com.br/Cracking-Coding-Interview-Programming-Questions/dp/098478280X)
+  - [Algorithm in Nutshell](http://www.amazon.com/Algorithms-Nutshell-In-OReilly/dp/059651624X)
+  - [Advanced Data Structures and Algorithms](https://books.google.com.br/books/about/Advanced_Data_Structures_and_Algorithms.html?id=9mBJ0CpKXdkC&redir_esc=y)