What are the sources for all the VC runtime package versions?

Question

Not quite sure how the question should be asked, but essentially our project has been plagued with incompatability difficulties with the VC runtime since 2005. Aside from the coding aspect of handling the compatability issues, can someone point me at an article that might identify the source of each VC runtime package?

For instance, some time ago we have downloaded VCRT 2008 version which I can't find on Microsoft's site anymore, and I can't actually work out where it came from.

For instance, where are the following from:

"9.0.30729.17" (VC2008 SP1)

"9.0.30729.01" (VC2008)

"9.0.21022.08" (VC2008)

What is the difference between the latter two?

Thanks