Those people that attended Erwin Vervaet's "Temporal Issues in a Rich Domain Model" presentation at The Spring Experience 2007 earlier this month, will be happy to learn that the source code discussed in that talk is now available. The code can be found in the following Subversion repository (ignore the certificate warning): https://svn.ervacon.com/public/projects/bitemporal/trunk/. For more details, see the readme.