All the students in a course I was teaching apparently were using Chegg for the previous year’s textbook so I decided to use as a supplement (to Strang [which was not the previous year’s book but had all the answers online anyway]) an old Mir publishers book on Diff Eq which I can’t remember exactly how I got (either a bookstore in the French quarter or maybe a library remainder sale).
At any rate it turns out the English printing is so rare not only can it not be found on Libgen - the few copies online are selling for hundreds of dollars (which I certainly would not have paid for it). So not only did I luck into a paper fortune (I suspect this is a rather illiquid market - plus I had to go through and fix a bunch of typos by hand, so much for the Soviet STEM educational complex) the kids _definitely_ couldn’t find this on the Internet.
I may soon - there is a book scanner in the med school library and I doubt very much they care about a Soviet copyrighted book (if USSR even asserted such a thing abroad or Russia does now for them).
At any rate it turns out the English printing is so rare not only can it not be found on Libgen - the few copies online are selling for hundreds of dollars (which I certainly would not have paid for it). So not only did I luck into a paper fortune (I suspect this is a rather illiquid market - plus I had to go through and fix a bunch of typos by hand, so much for the Soviet STEM educational complex) the kids _definitely_ couldn’t find this on the Internet.