My research has turned up many resources. Some more useful than others, but all interesting. I've collected the most interesting here.
These Autograph Albums Are Filled With Ghostly Inkblots
The most thorough write up on the ghost books.
Hey Dead Guy blog post
A brief blog post about the ghost books and their history.
Our Warwickshire
A short article with brief information on the books and Cecil. it mostly focuses on a family's signatures in one specific book of their collection.
Inherited Values article
Focuses on the story of Samuel T.A. Loftis and his book.
Autograph Ghosts of Famous People
Unknown newspaper article about ghost signatures and local interest.
About Autograph Books
A good primer on the history of autograph books.
The House of Stokes: 1881-1926 A Record
This book does not mention any of their autograph books, but interesting nonetheless.
The Life of Bishop Percival by Bishop William Temple
Gives a good account of the life of Cecil's father-in-law, John Percival.
Book Binders of Victorian London by Maurice Packer
A thorough guide to bookmakers in Victorian London.
Album Verses and Romantic Literary Culture by Samantha Matthews
A wonderfully researched look into the history of autograph books and how their impact was much more far reaching that a personal keepsake.
Elizabeth Neel's 2023 Exhibition Ghosts of My Friends
Neel's wonderful work in this exhibit "probes painting’s capacity to act as an index for cherished people, places, events and rituals." Really lovely work.
Want to make your own book of ghost signatures? Reflections of my Friends have a kit to get you started.