Now available on OTN, Integration with Fusion Applications is a 54-page sample chapter from The Oracle Fusion Applications Development and Extensibility Handbook, (2013, Oracle Press), by Vladimir Ajvaz, Oracle ACE Anil Passi, and Dhaval Metha.
If "free" isn't enough of an incentive for you to read that sample chapter, you can at least spend a few minutes watching this video interview with Vladimir Ajvaz and Anil Passi in which they describe in detail what that chapter covers and what you'll get out of it.