A lot of additional information on CDI can be found online. Regardless, the CDI specification remains the authority for information on CDI. The spec is less than 100 pages and is quite readable (don’t worry, it’s not like your Blu-ray player manual). Of course, it covers many details we’ve skipped over here. The spec is available on the at the JCP website (CDI 1.0) (CDI 1.1).
The CDI reference implementation, Weld, is being developed by the Weld team. The team and the CDI spec lead blog at in.relation.to. This guide was originally based on a series of blog entries published there while the specification was being developed. It’s probably the best source of information about the future of CDI and Weld.