How do you deal with attribution of a work that is derived from a work that is itself derived from an original work protected under CC BY-SA?
And while we're at it, let's push it further: Let's call the original work "Work0" and its author "Author0", the first derivative "Work1" and its author "Author1", and so on.
As AuthorN, to whom should I give attribution? All the previous authors? Only the one before me, AuthorN-1? Or only the original Author0?
If a license requires attribution of the original authors/copyright holders when you create a derived work, then that means you need to give attribution to all copyright holders.
If Jane creates Work0, which is then adapted to Work1 by Alice, then the copyright of Work1 is shared between Jane and Alice.
This means that, if the work is under a CC-BY license and Bob uses Work1 to create a derived work Work2, then Bob needs to attribute both Alice and Jane.
