There are a couple of good books on bitemporality, Richard Snodgrass' "Developing time-oriented database applications in SQL" is pretty much the bible on the subject and goes into great detail. "Managing Time in Relational Databases" by Tom Johnston and Randall Weis is another great book, a little more hands on with the code.
I'd love to see someone translate the concepts in both books to a useful postgres package. As Snodgrass points out, "Unfortunately, due to the noncompliance of all existing DBMSs, a few of these fragments run on no existing platform" and thus only discusses how they can be applied to DB2, MSSQL, Sybase, Oracle8 and UniSQL.
I'd love to see someone translate the concepts in both books to a useful postgres package. As Snodgrass points out, "Unfortunately, due to the noncompliance of all existing DBMSs, a few of these fragments run on no existing platform" and thus only discusses how they can be applied to DB2, MSSQL, Sybase, Oracle8 and UniSQL.