If these books are easy enough to get hold of we could always get them translated and then released on the internet somewhere or if you know the author get permission to translate which is highly unlikely.. this way the books will be out there for everyone to enjoy !! 
That is my worry entirely on producing a well referenced book. That it becomes freely available on the internet and sales are thus limited. I fail to gain a return on my long learned knowledge and the effort to produce a quality resource. It is the same reason once great factual websites have discontinued some of their more in depth analysis of data on various topics. They found that their work was being taken, and posted elsewhere, and then misused, in some cases, to make money for someone else. I seem to be a bit of a loan voice on all this, but knowledge is something that is normally gained by some kind of effort. It would be wonderful to have it freely available. However if there is free information, who is motivated to do the research and then present it in bite sized, friendly chunks. A decreasing number of people who have the time and ability to do so free of charge. And we know that system works as there have been calls for many wonderful things on this very website. Encyclopedia of cars in pictures. A library of members cars etc etc. The stumbling block is ever - who is to do the graft to put the idea into practice. Silence.
The only protection a product has is copyright. That is only as good as the legal procedure to initiate it. In this modern world copyright is failing. Intellectual theft is on the increase. Its been a problem with the UK as our Government has been subordinated to the EU. Neither has been robustly protecting British copyrights and patents as they should. Result, a great deal of lost revenue, on lost profit. Yet the public queue up to throw their intellectual property away free on Facebook and other pirate sites. There are several pictures I specifically did not want published. But they were posted by others. Now those pictures belong to to someone else and continue to pop up without so much as a by or leave. A secret is only a secret if you do not tell anyone, so sadly many collections are now behind closed doors, not accessible but to very few, no cameras or phones.
So I have rejected going down that route to publication of a encyclopedia of microcars like the English Deutsch Klienwagon, the same as I have on a set of manuals to help get cars going. I do not think the return is there for my efforts to create the product, in part due to intellectual theft. My writing is directed to other forms of prose, which whilst factual, contains plot and tale. Like those wonderful Arthur Ransome books including Swallows and Amazons. Many a youngster learned to sail from that book, it tells you all you need to know to get started. You do not even know your learning when you read it. That is the way to do it, I think.
Sorry to hang this on what was probably a frivolous comment that we would all like to see come true in a swine free world. Its an observation, not an answer.
