Well, I also had a copy under CVS (enough said, again) on a web site that disappeared since then… I still have the binaries and source code for the games I produced with it, though, but they were built for Classic MacOS. I had a backup on a Jaz drive, enough said. The problem is that this is one of the cases where I lost the source code. This apparently rekindled some interest in these old HP calculators, and someone asked him about HPDS (HP Development System), an assembler for the HP-48 that I had written way back then. The 1990s are calling, they want their development tools back The books are about the HP Saturn-based calculators, like the HP-48.
A friend of mine, Paul Courbis, has recently re-published old books of his on Amazon.