Happy Plants  
   Deals with Cleve Backster's experiments and other mind/plant experiments, including ones backing up Backster.
   http://www2.cedarcrest.edu/academic/writing/pleasure09/wallflowers.htm

Chapter Six- Cleve Backster's Laboratory  
   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.
   http://www.biomindsuperpowers.com/Pages/RealStoryCh6.html

Subtle Energy  
   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.
   http://www.lightworks.com/MonthlyAspectarian/1998/May/0598-05.htm

Vignettes From the History of Plant Morphology  
   Articles about people, mostly Agnes Arber, who created unconventional theories about plant morphology.
   http://members.aol.com/cefield/hauke/contents.html

Plant Articles by Judith Handelsman  
   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.
   http://here-and-now.org/judith/articles.html

Sacrifice for Science  
   Contains some information on Cleve Backster's experiments and the author's interpretations of the implications.
   http://www.hotguano.com/Tabari/otrhog/sacrifice.html