Since at least a month (https://github.com/SeerLabs/CiteSeerX/issues/87) all links to the open literature portal CiteSeerX redirect to the Wayback machine. The site was routinely used for academic literature references, of which at least 30'752 on Wikipedia based on Linksearch: https://en.wikipedia.org/w/index.php?title=Special:LinkSearc...

Aaargggh. That is terrible news. There's a metric shit-ton of good stuff in CiteseerX. If the site is gone for good, I sure hope there's a plan to properly move all that content to archive.org so it can remain accessible. :-(