Some older posts on this forum may refer to links on www.matrixmultimedia.com, an old web domain that we no longer use.
We have moved a lot of the old articles and resources to our matrixtsl.com site and you may be able to find them via a search on this page:
https://www.matrixtsl.com/resources/
So if you find a dead link to a resource, then you might be able to find it there.