@RustyBertrand I find it more difficult to locate a way to contact them at all. Either they have left the academia, or there is no email available.

I've also found one article that the author uploaded for free on their personal space, but as I forgot to download it, the whole domain became inaccessible after a couple of weeks. I found it interesting that this was a couple of months ago, and the university he belongs to was a popular one from Israel. One could speculate what happened.