How Sir William Crookes came to Believe in Spirits: Nandor Fodor
- Chapter on Florence Cook and Sir William Crookes in Nandor Fodor's book These Mysterious People.
- http://www.survivalafterdeath.org/books/fodor/chapter5.htm

Researches into the Phenomena of Spiritualism: Sir William Crookes
- Crookes' essays and letters on spiritualism, including several devoted to the study of Florence Cook's mediumship.
- http://www.survivalafterdeath.org/books/crookes/researches/contents.htm

Florence Cook & Katie King
- Haunted Museum article on Cook, with photographs.
- http://www.prairieghosts.com/florence.html

Pioneers: Florence Cook
- Biography of the medium who manifested the spirit of Katie King, and was championed by Sir William Crooks.
- http://www.fst.org/cook.htm