Recording availability?

[IllBeBach]

I've recently been reading about older pianists in the Harold Schonberg Great Pianists as well as the David Dubal Art of the Piano books.  They both refer to a lot of old recordings that as far as I can tell are out of print or not available.  Does anyone know where you can acquire old recordings of pianists from the very earliest period of the 20th century?

One source referred to the "IPA" which apparently stands for the International Piano Arcive.  Does anyone know anything about this?  I couldn't find anything online about it.

What I think would be cool is a deluxe edition of the Schonberg or Dubal works that includes excerpts of the recordings referred to.