Concurrency control resources

http://www.agiledata.org/essays/concurrencyControl.html

http://publib.boulder.ibm.com/infocenter/soliddb/v6r3/index.jsp?topic=/com.ibm.swg.im.soliddb.sql.doc/doc/the.purpose.of.concurrency.control.html

http://www.tutorialspoint.com/dbms/dbms_concurrency_control.htm

http://www.cs.berkeley.edu/~brewer/cs262/cc.pdf