Dear All,

Please find the below url to study the apex 4.2 and enjoy the reading.

http://www.oracle.com/technetwork/developer-tools/apex/documentation/index.html

Full Library zip file has all the documents of 4.2

In addition to the above, read the below 11g Application Developer guide

http://docs.oracle.com/cd/E11882_01/appdev.112/e25518.pdf