Why did this journal retract two 1940s papers by Max Planck?

> The specific reason for the retractions was copyright violation, so there was nothing wrong with the actual papers from a scientific standpoint.

There is a reason why the German portmanteau word "Zensurheberrecht" ("Zensur": censorship; "Urheberrecht": the related concept to copyright in German law) exists.

Discussed a couple days ago:

Springer Nature has removed two studies by Max Planck (science.org) 389 points, 196 comments

https://news.ycombinator.com/item?id=48686834