A chapter in a web-based book by psychologist Ingo Swann. Deals with a trip made by Swann to Backster's laboratory and chronicles the first-hand experiment he witnessed.

Deals with Cleve Backster's experiments and other mind/plant experiments, including ones backing up Backster.

Contains much information on various mind/plant type experiments throughout history. Some people mentioned include Cleve Backster and J. Chandra Bose.

A series of articles from various magazines. The second one has relevance primary perception discoveries, as it describes Handelsman's own experiences with the phenomenon.

Contains some information on Cleve Backster's experiments and the author's interpretations of the implications.

An article in a web-based magazine by Paul von Ward Lightworks. Deals with Cleve Backster's mind-plant discoveries and the author's speculations about them.

Articles about people, mostly Agnes Arber, who created unconventional theories about plant morphology.