Added section of Concurrency Control

Author: adamretter

README.md

@@ -11,11 +11,12 @@ If you are reading this and taking the effort to understand these papers, we wou
   3. [Classic System Design](#system-design)
   4. [Columnar Databases](#column)
   5. [Data-Parallel Computation](#data-parallel)
-  6. [Snapshot Isolation](#si)
-  7. [Consensus and Consistency](#consensus)
-  8. [Trends (Cloud Computing, Warehouse-scale Computing, New Hardware)](#trends)
-  9. [Miscellaneous](#misc)
-  10. [External Reading Lists](#external)
+  6. [Concurrency Control](#cc)
+  7. [Snapshot Isolation](#si)
+  8. [Consensus and Consistency](#consensus)
+  9. [Trends (Cloud Computing, Warehouse-scale Computing, New Hardware)](#trends)
+  10. [Miscellaneous](#misc)
+  11. [External Reading Lists](#external)
 
 
 ## <a name='basic-and-algo'> Basics and Algorithms
@@ -76,6 +77,11 @@ Columnar storage and column-oriented query engine are critical to analytical wor
 * [Spanner](http://static.googleusercontent.com/media/research.google.com/en//archive/spanner-osdi2012.pdf) (2012): Spanner is "a scalable, multi-version, globally distributed, and synchronously replicated database". The linchpin that allows all this functionality is the TrueTime API which lets Spanner order events between nodes without having them communicate. [There is some speculation that the TrueTime API is very similar to a vector clock but each node has to store less data](http://www.cse.buffalo.edu/~demirbas/publications/augmentedTime.pdf). Sadly, a paper on TrueTime is promised, but hasn't yet been released.
 
 
+## <a name="cc"> Concurrency Control
+
+* [Concurrency Control in Distributed Database Systems](https://www.cs.berkeley.edu/~brewer/cs262/concurrency-distributed-databases.pdf) (1981): Reviews 48 principal methods of Concurrency Control in the know literature and consoldates them to present * Multi-version Concurrency Control* (MVCC).
+
+
 ## <a name='si'> Snapshot Isolation
 
 * [A Critique of ANSI SQL Isolation Levels](http://research.microsoft.com/pubs/69541/tr-95-51.pdf) (1995): Defines isolation levels in terms of phenomena, and shows that these and the ANSI SQL definitions fail to characterize several popular isolation levels. It also defines an important multiversion isolation type: *Snapshot Isolation (SI)*.