Looks like the original publisher (a company called Abelard Schuman Inc) is owned by Harper Collins. Maybe you could consider reaching out out to them?
https://norman.hrc.utexas.edu/Watch/fob_search_results_next....
https://norman.hrc.utexas.edu/Watch/fob_search_results_next....
Here's another thing you can do... search LinkedIn for people who previously worked at Harper Collins, and cold email a few of them and say "Hey, I see you used to work at HC, I'm trying to work on a deal with them, could I pick your brain for a few minutes". Quite a few people will likely happily agree to a brief phone call / video chat, to help you out. Talk to a couple of such people and there's a good chance one of them will be able to point you in the right direction, and maybe even give you a warm introduction to the person you need to talk to.