1. Adams, D. K. (1928). The inference of mind. Psychological Review, 35(3), 235–252.
2. Adler, R. W. (2007). Restoring Colorado river ecosystems: A troubled sense of immensity. Washington, DC: Island Press.
3. Alexander, S. (1920). Space, time, and deity: The Gifford lectures at Glasgow, 1916–1918. London: Macmillan.
4. Automaton. (2018, June). Oxford English Dictionary Online. Retrieved from
http://www.oed.com
.
5. Backster, C. (1968). Evidence of a primary perception in plant life. International Journal of Parapsychology, 10(4), 329–348.