Carlos S. Alvarado, Historical perspective in parapsychology: Some practical considerations, Journal of the Society of Psychical Research, vol. 51, no. 791, pp. 265-271, 1982; http://www.parapsychology.org/dynamic/info/reprints/Blog%206%20JSPR%20Article.pdf
Robin P. Foy, In Pursuit of Physical Mediumship, Janus Publishing, Cambridge, England, 1996.
Klaus Heineman and Miceal Ledwith, The Orb Project, Atria Books/Beyond Worlds, Cambridge, England, 2007.
Virginia M. Hummel: Orbs and the Afterlife: Survival of the Soul, Starchild10, 2017.
Dean Radin, The Conscious Universe: The Scientific Truth of Psychic Phenomena, HarperOne, reprint edition, 2009.
Konstantin Raudive, Breakthrough: Experiment in Electronic Communication with the Dead, Taplinger, 1971.
Zofia Weaver: Other Realities?: The Enigma of Franek Kluski's Mediumship, White Crow Books, 2015.
Dr. Melvyn Willin, Ghosts Caught on Film, David & Charles, Cincinnati, 2007.
Terrific website and community blog on physical mediumship by Robin Foy.
Website of Association TranceCommunication.
All about instrumental communication and the devices used.
Research into eight areas of consciousness, including survival of consciousness after death.
Dedicated to conducting world-class research on phenomena currently unexplained within traditional scientific disciplines.
Wonderful assortment of photos, especially those of spirit cabinets.
Voice recordings of direct voice communications with Leslie Flint.
A foundation whose goal is to create an integrative, evidence-based technology for spirit communication.