Yes, I had found that CMU repository. That's where I noticed the books
listed, related to the project. The only place I found Christaller,
Thomas was at ResearchGate.com. However, the hobby status of my project
and my lack of scientific credentials, I suppose is the reason I didn't
qualify for an account there. It appears Christaller has most if not all
of the book available electronically there.
Since I posted my this message, I managed to score a copy of the second,
mentioned title: _CONSAT: A System for Constraint Satisfaction_('89).
by Hans Werner Güsgen. It's quite good in describing a 'constraint'
strategy, which is used in Babylon; as it specifically points out.
So, I'm well enough on my way with the project source and this
I appreciate your reply in so much as it reminded me that I hadn't
looked for the other co-authors, or for that matter, the author of this