Bibliografía (15 obras)
Hauntings and Poltergeists
2007
Parapsychology, Philosophy and the Mind
2002
Education in Parapsychology
1999
The relentlessquestion
1990
The Case for dualism
1989
The importance of psychical research
1988
NEUE WEGE DER PARAPSYCHOLOGIE
1980
Parapsychology
1974
New directions in parapsychology
Parapsychology - the way ahead
Psychological sciences
1973
The existence of mind
1962
