Jack the Ripper reading list question

If a person has read Donald Rumbelow's book on Jack the Ripper (variously published as The Complete Jack the Ripper and Jack the Ripper: The Complete Casebook), are there any other nonfiction Jack the Ripper books that one ought to read? I.e., has anything substantially new been said since Rumbelow? (And should I bother with anything pre-Rumbelow?)

Please note, I'm not asking what books about Jack the Ripper have been published since 1975; I can find that out for myself. I'm asking for recommendations about which, if any of them, to read.