We are now in the Age of Censorship. If you find a link that is not available, a copy of it may be in the Wayback machine at https://archive.org. Just enter the real URL into the Wayback Machine and hit Enter to search for it. You will see a calendar and each date with a circle means the site has a copy of that web page made on that circled date.
Do they save PDFs? They did not save PDFs for many years but recently it seems they have started supporting that.