[QTI] n00b Questions

[Clarence Klopfstein]

So I'm am tasked with converting QTI documents to a proprietary
format, and I have two basic questions.
1. Where can I find the best specification?  I've downloaded what they
call the Final Specification Version 1.2, but it misses a lot of the
details about why something is where it is.
2. What is the difference between a document that has the 'assessment'
node and a document that doesn't?

Thanks,
Clarence Klopfstein