William Pugh, one of the authors of "JSR-133: Java Memory Model and Thread Specification" maintains a webpage about the memory model here:
http://www.cs.umd.edu/~pugh/java/memoryModel/
The complete JSR-133 can be found here:
http://www.cs.umd.edu/~pugh/java/memoryModel/jsr133.pdf
Also relevant is the Java Language Specification, Section 17.4 Memory Model:
http://docs.oracle.com/javase/specs/jls/se7/html/jls-17.html#jls-17.4