Documentation
Tutorials and introductory papers
A general introduction to Cadabra can be found in
For a slightly more technical introduction, specifically targeted at high-energy physicists, see the paper
Leo Brewin has written a nice introduction to Cadabra for people who intend to use it in General Relativity,
also available as arxiv:0903.2085
Finally, there are also some tutorial-style examples in the reference guide (see below).
Context-sensitive help
Pressing 'F1' in the graphical notebook interface when the cursor is over the name of an algorithm or property will pop up the associated section in the reference guide. A list of all algorithms and properties is available from the help menu.
Reference guide
An extensive reference manual of the program, with a description of the input language, the algorithms and technical details on how to extend it by adding new C++ modules, is available as
preprint AEI-2006-038last version: December 23rd, 2008
Technical papers
A more technical explanation of the motivation for writing this software, as well as a sketch of the internal structure, can be found in the paper
Source code documentation
If you are interested in the internals of the program, there is some doxygen documentation, though this is still in a rather preliminary stage.
You can browse the entire source tree using the public GIT repository.
For a history of the changes made since the first release, consult the ChangeLog.