Thought Field Therapy offers a variety of tapping sequences for different kinds of healing. They have tapping protocols for trauma, phobias and much more. Healing Key Way uses some of these, and you may wish to investigate these for your own use.
Tapas Fleming is the originator of the Tapas Acupressure Technique (TAT), a simple "hold" using the hands on the head. It improves healing, reduces stress, calms the mind and assists in accessing memories. It is used in the Healing Key Way protocol to assist in accessing stories and calming the mind and emotions.
Barbara Ann Brennan is a scientist, healer and therapist who has done extensive research on the human energy field. She worked for NASA and went on to train in bioenergetics. Her books - Hands of Light and Light Emerging - are on the Book List and are considered classics in alternative healing methods.
Emotional Freedom Technique is a tapping sequence used for emotional balancing and healing. The sequence is less specific than the Callahan Techniques but still useful.
Donna Eden is one of the pioneers of energy medicine. Her famous book Energy Medicine is a classic. She and husband David Feinstein continue to offer information and trainings about their energy techniques for medicine, psychology and self-care.
Eckhart Tolle's words, whether written or spoken, are profound. He gives the best description I've ever heard of how the ego works. His two most well-know books — The Power of Now and A New Earth — are on the Book List. His web site contains a great question and answer section.
Marcel Vogel was a brilliant pioneer and exacting researcher in the field of crystal technology and the safe and effective use of crystals for spiritual healing. He was the first researcher to create liquid crystal, now used widely in electronics. He also had a deeply spiritual side, and IBM gave him the freedom to work on crystal research in whatever way he chose. His work is carried on by Rumi Da. I highly recommend their training DVD's, healing crystals and Star of David medallions. Contact me or the folks at Vogel Crystals with questions if you are thinking of purchasing.
Tom Kenyon is a therapist, healer, author and spiritual teacher based in western Washington State. He is one of the few spiritualists I can recommend, because he is not tainted in any way by ego or the dangerous type of dabbling in psychic matters which so many spiritualists fall prey to. His website has wonderful information and CD's for healing and learning.
Another spiritual healer and teacher I trust is Livina Hiacinth, a woman who does private readings/healings. She is a lovely person, powerful Light reader and humble helper on your journey..