[adrian17]

This probably depends on country, but AFAIK in most of europe, even in public domain, the „you can’t pass another’s work as your own” part of copyright is still active and doesn’t expire.

[poly2it]

This piques my interest, what is the legally required recognition of a derivative's parent work? Must I be able to list dependencies, or should I be able to verify whether a parent work is included in mine? What if my work is a second derivative of a work which I am unaware of, because the work in between improperly didn't recognise its parent? Am I legally responsible to investigate such cases?

[projektfu]

Something like, "Pride and Prejudice and Zombies, by Jane Austen and Seth Grahame-Smith" is probably sufficient.