old releases of PostgreSQL ?

I am a graduate student studying at University of Waterloo. Now I am researching on the topic of Software Evolution. PostgreSQL is one of the "open source" example I am trying to investigate. My method is to use software reverse-engineering and visualization tool to analysis the evolution pattern of "open source" project.

I downloaded all the old distributions of postgreSQL source code, but failed to find out the following versions:

Release 6.4.1
Release 6.4
Release 6.3.2
Release 6.3.1
Release 6.3
Release v6.0
Release v1.09

I understand Ingres of the grandfather of all IngresII, postgres95 and postgreSQL. However, only the last version 8.9 can be founded on the ftp sites. I though it could be interesting to include Ingres evolution history into my research, in order to investigate the impact of Internet collaborate on traditional "open source" project evolution. It will be very helpful if you can show me where can I find out all the past releases of Ingress prior to version 8.9