edited by Jane Henry
Routledge, 2005
Buku Teks SO
edited by J. Gordon Melton
Gale Group, 2001
Buku Referensi
Bentine, Michael
Granada , 1981
Buku Teks SO
Karolyi, George
The Paranormal Phenomena Research Foundation, 2009
Buku Teks SO
Brooks, Fowler D.
Houghton Mifflin, 1929
Buku Teks