This week's book giveaway is in the OCAJP 8 forum. We're giving away four copies of OCA Java SE 8 Programmer I Study Guide and have Edward Finegan & Robert Liguori on-line! See this thread for details.
That sounds a little snide when taken out of context, but the answer is 'yes', there are three key documents that make up JSR220, which is better known as the EJB3 spec.
The simplified API is a great read! Core contracts is like the Simplified API document on speed and steroids!
The Java Persistence API document explains how database stuff is done in EJB3. There really aren't any 'entity beans' anymore in EJB3, but instead, Java POJOs that represent 'entities.' Ok, the difference is subtle, but it's significant!