Reissued Titles

I'm sure this has been answered before but I searched and couldn't find an answer so here goes - What is the correct way to handle this kind of situation?
https://www.librarything.com/nseries/120260/Cuvier-Widows-Trilogy

The books were reissued with the one word titles, should I combine the old titles into the newer titles or leave both and list both in the series?

Thanks for guidance.

If they are the same books, they need to be combined regardless of the title, language or author name being used.

If they are substantially revised, that can change things a bit but these do not seem to be so yep, go they need to be combined.

It would be good to enter original titles and alternative titles in CK, letting the work title be decided by the computer.

>3 MarthaJeanne: Yep.

Having the books combined, whether it is a reissue or different titles in the US and the UK is so helpful when you come across a 'new title' by an author. You look it up and see, 'Oh I have already read this, just with a different title. Don't need to buy this one.'